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واژه نامه سیستم پیجینگ IP

نیاز به راه اندازی سیستم صوتی و یا سیستم پیجینگ IP شما را با کلماتی جدید روبرو خواهدکرد. واژه نامه ای را تهیه کرده ایم که با تکمیل آن کوششی در راستای فرهنگ سازی و کمک به مشتریان و همکاران عزیزمان داشته باشیم.

Air Plenum


پلنوم Plenum فضای خالی بالای سقف یا زیر کفپوش است که نقش مخزن چرخش هوا را بازی و به گرمایش و سرمایش اتاق‌ها کمک می‌کند.

 

Alert Tone
 

Alert Tone یا صدای هشدار، یک نوع صدای کوتاه و قوی است که برای جلب توجه کاربر در مواقع اضطراری یا هشدارهای مهم استفاده می‌شود. 

 

All Call
 

در سیستم‌های صوتی، عبارت "All Call" به معنای ارسال پیام صوتی به تمام اعضای یک گروه یا تمام دستگاه‌های متصل به سیستم اشاره دارد. وقتی که یک پیام "All Call" فرستاده می‌شود، صدای آن به همه اعضا یا دستگاه‌های متصل به سیستم منتقل می‌شود و همه می‌توانند آن را بشنوند. این ویژگی معمولاً در مکان‌های عمومی، مانند فرودگاه‌ها، هتل‌ها، مراکز خرید و غیره، برای اطلاع‌رسانی به تمام کاربران یا مشتریان استفاده می‌شود.

 

Ambient Noise
 

Ambient Noise به معنای نویز محیطی یا صداهای پس‌زمینه است که در محیط وجود دارد و ممکن است تأثیراتی بر کیفیت صدای سیستم صوتی داشته باشد. این نویز‌ها ممکن است از منابع مختلفی مانند تردد خودروها، صدای گفتگوها، صدای دستگاه‌های الکتریکی و غیره باشند. در سیستم‌های صوتی، مدیریت Ambient Noise مهم است تا کیفیت صدا و انتقال پیام‌های صوتی به صورت واضح و دقیق برقرار شود. استفاده از فناوری‌های کاهش نویز و تنظیمات مناسب می‌تواند به بهبود عملکرد سیستم صوتی کمک کند.

 

Amphenol

Amphenol یک شرکت بزرگ و معتبر در زمینه تولید اتصالات و کانکتورها است که در صنعت الکترونیک و ارتباطات فعالیت دارد. این شرکت انواع محصولات اتصالاتی و کانکتورهای مختلفی را تولید می‌کند که در سیستم‌های صوتی نیز استفاده می‌شوند.

در سیستم‌های صوتی، کانکتورها و اتصالات Amphenol می‌توانند به عنوان واسطه‌های موثر برای اتصال اجزای مختلف سیستم صوتی به یکدیگر استفاده شوند. این کانکتورها به طور عمده برای اتصال بلندگوها، میکروفون‌ها، دستگاه‌های پخش صدا و سایر قطعات سیستم صوتی استفاده می‌شوند.

Amphenol با تمرکز بر کیفیت و دقت در تولید، محصولات با عمر طولانی و عملکرد بالا را ارائه می‌دهد. استفاده از کانکتورها و اتصالات Amphenol در سیستم‌های صوتی می‌تواند به بهبود کیفیت صدا و پایداری اتصالات کمک کند.

Amplifier
 

آمپلی‌فایر صوتی یک دستگاه الکترونیکی است که وظیفه تقویت و افزایش قدرت سیگنال صوتی را بر عهده دارد. این دستگاه برای افزایش قدرت صدا و ایجاد صدای قوی‌تر و واضح‌تر در سیستم‌های صوتی استفاده می‌شود. آمپلی‌فایر صوتی به عنوان یک پل بین منبع صوتی (مانند میکروفن یا دستگاه پخش صوت) و بلندگوها عمل می‌کند.

به طور کلی، آمپلی‌فایر صوتی دارای ورودی‌های صوتی است که سیگنال‌های صوتی را از منبع صوتی دریافت می‌کند. سپس این سیگنال‌ها را تقویت کرده و به بلندگوها منتقل می‌کند تا صدای تقویت شده و با کیفیت به گوش شنونده‌ها منتقل شود.

Atom Feed

Atom Feed در واقع یک فرمت استاندارد برای انتقال و انتشار محتواهای وب است. این فرمت به طور عمده برای انتقال اطلاعات مانند متن، تصاویر، ویدیوها و صداها استفاده می‌شود. Atom Feed معمولاً برای انتشار مطالب وبلاگ‌ها، خبرگزاری‌ها، پادکست‌ها و سایر منابع محتوای دیجیتال استفاده می‌شود.

در سیستم صوتی، Atom Feed می‌تواند برای انتقال پادکست‌ها یا فایل‌های صوتی مورد استفاده قرار بگیرد. با اشتراک گذاری Atom Feed یک پادکست، کاربران می‌توانند از آخرین قسمت‌های پادکست مورد علاقه خود مطلع شوند و به راحتی آن‌ها را پخش کنند.

Attenuation
 

به تضعیف شدن سیگنال صوتی اشاره دارد.

Audible Frequency
 

فرکانس قابل شنیدن یا "audible frequency"، محدوده‌ای از فرکانس‌های صوتی است که انسان قادر به شنیدن آنها است. بیشتر افراد قادرند فرکانس‌هایی را که بین 20 هرتز (Hz) تا 20,000 هرتز (Hz) واقع شده‌اند، بشنوند. این محدوده فرکانس‌ها بین حداقل و حداکثر فرکانس‌های قابل شنیدن توسط انسان است. هر فرکانس مختلف می‌تواند به یک نوع صدا یا نت منطبق با آن فرکانس منجر شود.

 

Automatic Gain

Automatic Gain یا AGC، یک فناوری در دستگاه‌های الکترونیکی است که بیانگر قابلیت تنظیم خودکار سطح ولتاژ ورودی یا خروجی است. این فناوری به دستگاه‌های الکترونیکی اجازه می‌دهد تا خودکار سطح ورودی یا خروجی خود را بهینه کنند و از نوسانات ناخواسته در سطح سیگنال جلوگیری کنند.

در بسیاری از دستگاه‌های صوتی، مانند رادیو، تلویزیون، ضبط صوتی، و تجهیزات صوتی حرفه‌ای، AGC برای تنظیم خودکار سطح صدا استفاده می‌شود. این فناوری به دستگاه اجازه می‌دهد تا با توجه به شرایط مختلف محیط، مانند نوسانات شدت صدا، خودکار سطح ولتاژ صدا را تنظیم کند تا صدای خروجی همواره در یک محدوده قابل قبول باشد و از افزایش یا کاهش ناگهانی صدا جلوگیری کند.

AGC همچنین در دستگاه‌های الکترونیکی دیگر، مانند رادار، دستگاه‌های پردازش سیگنال، و تجهیزات ارتباطات بی‌سیم نیز استفاده می‌شود.

Automatic Volume Control (Antiblast Control)

Automatic Volume Control (AVC) یک فناوری در دستگاه‌های صوتی است که بیانگر قابلیت تنظیم خودکار سطح صدا است. AVC به دستگاه‌های صوتی اجازه می‌دهد تا خودکار سطح صدا را بهینه کنند و از نوسانات ناخواسته در سطح صدا جلوگیری کنند.

در بسیاری از دستگاه‌های صوتی، مانند رادیو، تلویزیون، ضبط صوتی، و تجهیزات صوتی حرفه‌ای، AVC برای تنظیم خودکار سطح صدا استفاده می‌شود. این فناوری به دستگاه اجازه می‌دهد تا با توجه به شرایط مختلف محیط، مانند نوسانات شدت صدا، خودکار سطح صدا را تنظیم کند تا صدای خروجی همواره در یک محدوده قابل قبول باشد و از افزایش یا کاهش ناگهانی صدا جلوگیری کند.

AVC همچنین در دستگاه‌های الکترونیکی دیگر، مانند رادار، دستگاه‌های پردازش سیگنال، و تجهیزات ارتباطات بی‌سیم نیز استفاده می‌شود.

 

 

Bandwidth
 

پهنای باند شبکه معیاری است که حداکثر ظرفیت یک لینک ارتباطی سیمی یا بی سیم را برای انتقال داده‌ها از طریق اتصال شبکه در مدت زمان معین نشان می‌دهد. معمولا Bandwidth برحسب بیت، کیلوبیت، مگابیت یا گیگابیتی نشان داده می‌شود که می‌تواند در 1 ثانیه منتقل شود.

 

Battery Backup

 باتری بک آپ برای ارائه یک منبع برق پشتیبان  به تجهیزات شبکه و سیستم صوتی مورد استفاده قرار می گیرد که در مواقع قطع برق اصلی تجهیزات می توانند از آن استفاده کنند.

Battery Feed (BF)


منبع تغذیه باتری یا سیستمی که برق را از باتری به دستگاه یا سیستم مورد نظر تامین می‌کند

 

BGM
 

مخفف موسیقی پس زمینه است

Bridge

 در سیستم های صوتی اشاره به پلی دارد که برای استحکام سقف های کاذب به منظور نگه داشتن بلندگوی سقفیمورد استفاده قرار می گیرد. 

Bridging Clips
 

گیره های فلزی که برای اتصال دو نیمه یک بلوک پانچ شده در سقف های کاذب استفاده می شود.

 

Browser Based Server
 

منظور سرور های سیستم پیجینگ و اینترکام که برای تنظیمات آن از برازر هایی مثل کروم، فایرفاکس و اینترنت اکسپلورر استفاده می شود.

 

Butt Set (Lineman’s Handset)
 

به تستر خط تلفن که در بازار به گوشی های غلامی معروف است اشاره دارد

Call Button
 

دکمه ای است که با فشردن آن می توان با یک داخلی یا شماره خاص مثل اورژانس تماس گرفت. این داخلی در پنل تنظیمات دستگاه صوتی که Call Button دارد قابل تغییر است.

 

Calling Party Control (CPC)
 

سیگنالی که از یک سیستم تلفن یا یک ارائه دهنده خدمات تلفنی به تجهیزات مشترک تلفن ارسال می شود تا نشان دهد که طرف تماس تلفن را قطع کرده است. 

 

Central Office (C.O.)

منظور دفتر مرکزی یا ساختمان مرکزی می باشد که تجهیزات کنترل سیستم صوت در ان قرار داده می شود.

 

C.O. Line Port (Loop Start)
 

منظور پورت هایی روی مرکز تلفن است که خطوط تلفن سیمی دریافتی از مخابرات به آن متصل می گردد.

Centrally Amplified System
 

سیستم آمپلی فایر مرکزی اشاره به رک صوتی دارد که آمپلی فایر های سیستم صوتی در آن متمرکز شده است.

Centrex (Hosted Telephone Service)
 

خدمات تلفنی ارائه شده از طریق یک سرویس دهنده تلفن است که بسیاری یا همه ویژگی های یک (مرکز تلفن) PBX را بدون هزینه نگهداری سوئیچ خصوصی در اختیار کاربر نهایی قرار می دهد. این سرویس از سرویس دهنده تلفنی خریداری شده است. و نیازی به تجهیزات "در محل" ندارد.

 

Closed Loop

در سیستم‌های الکترونیکی، مفهوم "closed loop" به وضعیتی اشاره دارد که در آن یک بازخورد (feedback) برای کنترل و تنظیم عملکرد سیستم استفاده می‌شود. در یک سیستم closed loop، خروجی سیستم به عنوان ورودی به سیستم بازخورد می‌شود تا عملکرد سیستم بر اساس خروجی فعلی تنظیم شود.

برای مثال، در یک سیستم کنترل دما، یک سنسور دما ممکن است دمای فعلی را اندازه‌گیری کرده و این اطلاعات به یک کنترلر ارسال کند. کنترلر بر اساس دمای فعلی، تصمیم می‌گیرد که آیا باید گرمایش یا خنک‌کن در سیستم فعال شود یا خاموش بماند. این بازخورد بین خروجی (دما) و ورودی (تصمیم کنترلر)، نشان‌دهنده یک سیستم closed loop است.

سیستم‌های closed loop معمولاً بهبود عملکرد و پایداری سیستم را فراهم می‌کنند، زیرا این امکان را فراهم می‌کنند که سیستم به تغییرات خارجی و داخلی واکنش نشان دهد و خود را تنظیم کند.

Combination Paging
 

اگر "Combination Paging" به معنای ارسال پیام به گروه‌های مختلف یا دستگاه‌ها با استفاده از ترکیبی از روش‌ها یا فنون مختلف باشد، ممکن است اشاره به استفاده همزمان از روش‌های مختلف ارسال پیام باشد. برای مثال، استفاده همزمان از پیام‌رسانی صوتی، پیامک، ایمیل و ... به منظور اطلاع‌رسانی به گروه‌های مختلف افراد یا دستگاه‌ها.

 

Common Alert Protocol

سیستم های هشداردهنده و ارتباطات بحرانی است. این استاندارد برای تبادل اطلاعات مربوط به هشدارها، اطلاعات جغرافیایی، پیام‌های اضطراری و دیگر اطلاعات مربوط به مدیریت حوادث و بحران‌ها استفاده می‌شود.

استفاده از Common Alerting Protocol (CAP) در سیستم‌های صوتی می‌تواند به این معنا باشد که پیام‌های هشدار و اضطراری با استفاده از این استاندارد ارسال می‌شوند. این استاندارد می‌تواند به عنوان یک رابط بین سیستم‌های مختلف صوتی و سایر سیستم‌های هشداردهنده استفاده شود تا اطلاعات هشدار و اضطرار را به صورت یکپارچه و قابل فهم برای سیستم‌های صوتی منتقل کند.

با استفاده از CAP، می‌توان پیام‌های هشدار و اضطرار را به صورت استاندارد و قابل پردازش برای سیستم‌های صوتی ارسال کرد تا به طور خودکار پخش شوند و به افراد در معرض خطر هشدار داده شود.

بنابراین، استفاده از Common Alerting Protocol (CAP) در سیستم‌های صوتی می‌تواند بهبود قابلیت‌های هشداردهنده و اضطراری سیستم صوتی را بهبود بخشیده و روند ارسال و پخش پیام‌های هشدار را بهبود بخشد.

Common Battery


منظور برق روی خط تلفن است که از مخابرات مرکزی روی آن خط اعمال می شود.

Contact Closure

Contact closure در سیستم صوتی به تعدادی از ورودی‌ها یا خروجی‌های سخت‌افزاری اشاره دارد که با استفاده از اتصال یک سیم برقی (کانکشن) فعال می‌شوند یا غیرفعال. این نوع اتصال برقی معمولاً به عنوان یک رابط استاندارد برای کنترل و مدیریت سیستم‌های صوتی و تجهیزات مرتبط استفاده می‌شود.

 

Control Unit
 

در سیستم های پیجینگ آنالوگ، یک واحد کنترل رابطی بین کاربر، سیستم تلفن و سیستم صوتی است که می تواند امکانات کننترلی مختلفی را در کل سیستم اعمال نماید.

 

Cross Connect
 

در شبکه‌های کامپیوتری به یک نوع اتصال فیزیکی بین دستگاه‌ها یا تجهیزات شبکه اشاره دارد. این اتصال معمولاً به صورت یک ترکیب از کابل‌ها، پچ پنل‌ها و سوئیچ‌ها استفاده می‌شود تا ارتباط بین دستگاه‌های مختلف شبکه را فراهم کند.

در واقع، یک cross connect می‌تواند به عنوان یک نقطه اتصال مرکزی در یک شبکه مورد استفاده قرار گیرد که به کمک آن، ارتباط بین دستگاه‌های مختلف شبکه برقرار می‌شود. این نقطه اتصال معمولاً در یک محل مرکزی نصب می‌شود و به عنوان نقطه تماس بین دستگاه‌های مختلف شبکه عمل می‌کند.

استفاده از cross connect در شبکه‌های کامپیوتری به منظور اتصال دستگاه‌ها به یکدیگر، به تغییرات در توپولوژی شبکه و همچنین به تسهیل انجام عملیات نگهداری، تعمیر و تغییرات در سیستم‌های شبکه کمک می‌کند. به عنوان مثال، اگر نیاز به تغییرات در اتصالات فیزیکی شبکه و یا جابجایی دستگاه‌ها وجود داشته باشد، cross connect به عنوان یک نقطه اتصال مرکزی می‌تواند این فرآیند را سریع و آسان کند.

در کل، cross connect در شبکه‌های کامپیوتری به عنوان یک نقطه اتصال فیزیکی برای اتصال دستگاه‌ها و تجهیزات شبکه به یکدیگر استفاده می‌شود و به تسهیل عملیات مختلف شبکه کمک می‌کند.

 

Cross Connection (Interconnect)
 

روش های استفاده از کراس کانکت (با یا بدون پچ کورد یا جامپر).

Crosstalk
 

به تداخل ناشی از انرژی الکتریکی بین دو سیم هم‌شنوی یا کراس‌تاک یا نشت سیگنال می‌گویند و با نماد XT نمایش می‌دهند. به عبارت دقیق‌تر هم‌شنوی جفت‌شدگی ناخواستهٔ سیگنال‌ها بر اثر خاصیت القاوری یا خازنی بین دو کانال مخابراتی است. هم‌شنوی زمانی رخ می‌دهد که بخشی از انرژی سیگنال از کابل نشت می‌کند و در کابل دیگر دریافت می‌شود. به این نشت واپس‌روی می‌گویند. هم‌شنوی را می‌توان به دو دستهٔ همشنوی سرهای دور   و هم‌شنوی سرهای نزدیک  تقسیم کرد.

 

Daisy Chaining Cable
 

سیم کشی چندین دستگاه در یک سیم حلقه پیوسته.

dB (Decibel)
 

دسی‌بل معمولاً به عنوان واحد میزان فشار صدا شناخته می‌شود، ولی علاوه بر میزان صدا، دسی‌بل در بسیاری از اندازه‌گیری‌های علمی و مهندسی از جمله در زمینه‌های آکوستیک، الکترونیک و کنترل مورد استفاده قرار می‌گیرد. در الکترونیک، بهرهٔ تقویت‌کننده‌ها، افت سیگنال‌ها و نسبت سیگنال به نویز معمولاً برحسب دسی‌بل بیان می‌شوند.

 

dBspl
 

SPL کوتاه شده عبارت Sound pressure Level است و میزان بلندی صدا را بیان می کند. این پارامتر برای هر اسپیکری وجود داشته و معمولا با دستگاه های صدا سنج اندازه گیری می شود. بسته به این میزان فاصله از مرکز پخش کننده صدا چقدر باشد، میزان SPL متفاوت خواهد بود. واحد اندازه گیری SPL  با دسیبل  db بیان می شود.

 

Dial Tone
 

بوق آزاد (به انگلیسی: dial tone) یک سیگنال تلفنی است که با تشخیص وضعیت قلاب-قطع، توسط یک مرکز تلفن به یک تلفن ارسال می‌شود. این نشان می‌دهد که مرکز در حال کار است و برای شروع یک تماس تلفنی آماده است. در سیستم صوتی اولین صدایی است که وقتی فرد پیج کننده پیغام صوتی را به سمت بلندگو اراسل می کند یک صدای زنگ کوتاهی که قابل انتخاب است پخش می شود که به آن Dial Tone می گویند. گاها به آن زنگ پیش تماس هم گفته می شود. 

 

 

Distributed Self-Amplified System
The modern way to integrate analog public address announcements with a telephone system in which each speaker has a built-in amplifier and volume control, (a.k.a. the Valcom System). Compare: Centrally Amplified System

Dry Contact Closure
A switchable set of contacts with no potential difference between them or to any other reference point.

Dual-Tone Multi-Frequency (DTMF)
Use of two simultaneous voice band tones for signaling or dialing on a telephone keypad.

Eavesdropping
The act of monitoring an area without knowledge or consent of the occupants.

Electric Strike plate
An electro-mechanical door lock.

Endpoint
In Valcom VoIP systems, the terms endpoint and gateway are used to describe the actual Valcom network connected equipment. In general, the term endpoint is used to describe devices that provide information to users without any interaction on the user’s part (speakers, horns, LED signs) where gateway is the term used to interface to support equipment (audio sources, telephones, relays, etc)

Equalizer (EQ)
A device that modifies an audio signal through the use of multiple adjustable filters.

Extension Port
A port on a telephone system that is intended for connection to a system telephone or station level paging adapters. See Station Port.
Federal Communications Commission (FCC)
A U.S. government agency that regulates and monitors the domestic use of the electromagnetic spectrum for communications.

Feedback
The process of returning a fraction of the output energy of an energy converting device to the input. The circuit that transmits the feedback signal to the input is the beta circuit; the circuit containing the active device, which generates the output signal, is the mu circuit. In audio amplification systems, feedback results in an undesirable system wide squeal.

Feedback Elimination
A method of digitally delaying paging system announcements until the originating device is returned to an idle state. This breaks the feedback loop by delaying the announcement.

Frequency
The rate in hertz (cycles per second) at which a signal pattern is repeated.

Frequency Response
A measure of the effectiveness with which a circuit, device or system transmits the different frequencies applied to it. The way in which an electronic device (mic, amp or speaker) responds to signals having a varying frequency. This is a measurement of how well an amplifier reproduces and amplifies a specified audible range with equal amplitude or intensity.

FXO Port

Foreign Exchange Office - See C.O. Line Port

FXS Port

یک پورت با درگاه RJ11 برای اتصال تلفن و یا فکس آنالوگ به سیستم های تلفنی ویپ می باشد. FXS پورتی است که معمولا روی گیت وی(مبدل آنالوگ به دیجیتال و بالعکس) و مرکز تلفن های ویپ برای اتصال تلفن و فکس قرار داده می شود. پورت FXS روی مودم های فیبر نوری منازل نیز تعبیه می شود.

Gateway


یک ابزار در سیستم تلفنی ویپ برای ورود خطوط تلفن شهری و یا اتصال دستگاه های تلفن آنالوگ می باشد. گیت وی های ویپ دارای پورت های مختلفی هستند مثل پورت FXS، پورت FXO، پورت E1 و پورت GSM

Graphical User Interface (GUI)
 

Graphical User Interface (GUI) به معنای رابط کاربری گرافیکی است که به کاربر امکان می‌دهد با استفاده از عناصر گرافیکی مانند دکمه‌ها، منوها، پنجره‌ها و تصاویر با سیستم کامپیوتر یا نرم افزار تعامل داشته باشد. GUI یک رابط کاربری است که به کاربر امکان می‌دهد به طور بصری و با کلیک کردن بر روی عناصر مختلف، با سیستم یا نرم افزار ارتباط برقرار کند.

 

Granularity
 

در سیستم صوتی، مفهوم Granularity به معنای تعیین دقیق میزان جزئیات و رزولوشن صدا است. در واقع، Granularity در سیستم صوتی به تعداد نمونه‌هایی اشاره دارد که بیانگر تعداد بیت‌های استفاده شده برای نمایش هر نمونه از صدا می‌باشد. به عبارت دیگر، Granularity در سیستم صوتی نشان دهنده دقت و کیفیت نمایش صدا است.

 

Ground
 

round در سیستم صوتی به معنای اتصال به زمین یا اتصال به نقطه ارجاع الکتریکی است. Ground یک نقطه مشترک است که برای اتصال قسمت‌های مختلف یک سیستم صوتی به یکدیگر و به منابع تغذیه الکتریکی استفاده می‌شود.

Ground در سیستم‌های صوتی برای انتقال اطلاعات صوتی و انرژی الکتریکی به صورت امن و بهینه استفاده می‌شود. این نقطه ارجاع الکتریکی به عنوان نقطه صفر الکتریکی در سیستم صوتی عمل می‌کند و از آن برای تعادل و استحکام سیگنال‌های صوتی و الکتریکی استفاده می‌شود.

 

Ground Start
 

Ground Start یک روش معمول برای اتصال سیستم‌های صوتی به نقطه ارجاع الکتریکی یا زمین است. در این روش، یکی از سیم‌های منفی (بیشتر از همه سیم سیاه) به نقطه ارجاع الکتریکی یا زمین متصل می‌شود. این روش به عنوان Ground Start شناخته می‌شود زیرا سیم Ground به عنوان نقطه شروع یا Ground Start برای سیستم صوتی عمل می‌کند.

Ground Start در سیستم‌های صوتی به منظور جلوگیری از نویز و تداخلات الکتریکی، بهبود کیفیت صدا، و جلوگیری از خطرات الکتریکی استفاده می‌شود. این روش از اتصال مناسب Ground برای انتقال سیگنال‌های صوتی و الکتریکی به صورت صحیح و امن استفاده می‌کند.

 

Group Call
 

ترکیب گروه بندی شده ای از زون ها در یک سیستم پیجینگ چند بخشی که برای هدایت اعلان ها به مخاطبان هدف بدون ایجاد اختلال در سایر بخش ها استفاده می شود.

 

Half-Duplex
 

مداری که اطلاعات را در هر دو جهت حمل می کند، اما در هر زمان فقط در یک جهت

 

Head End Equipment
 

بخشی از سیستم پیجینگ یا سیستم تلفنی که همه اجزای سیستم از آن منشا می گیرند. بیشتر به رک های صوتی اشاره دارد.

 

Hertz (Hz)
 

واحد اندازه گیری که برای نشان دادن فرکانس صوت یا شکل موج الکتریکی استفاده می شود.

 

Home Run
 

اجرای سیستم پیجینگ با یک سیم اختصاصی برای هر بلندگو 

 

Hosted PBX
 

یکی از مهم‌ترین چالش‌های سیستم‌های PBX هزینه زیاد و زحمات نگهداری آنهاست که بر صاحبان کسب‌وکارها تحمیل می‌شود. این سیستم‌ها فاقد امکانات و ویژگی‌های پیشرفته هستند و در ظرفیت و مقیاس‌پذیری محدودیت دارند. همچنین، این سیستم‌ها با توجه به فراگیر شدن دورکاری در میان کسب‌وکارها، امکان برقراری تماس‌های کارمندان از راه دور را غیر ممکن می‌کنند. برای رفع این مشکلات می‌توان از خدمات مرکز تلفن میزبانی‌شده یا Hosted PBX برای برقراری ارتباط‌های تلفنی شرکت استفاده کرد.
هاستد پی بی اکس (PBX Hosted) یک مرکز تلفن ویپ است که توسط یک ارائه‌دهنده خدمات مرکز تلفن یا مرکز تماس میزبانی و سرویس آن ارائه می‌شود.

 

Impedance
 

مفهوم کلی‌تر مقاومت الکتریکی، و مقدار مقاومتی است که تحت یک اختلاف پتانسیل متناوب در برابر جریان الکتریکی متناوب ظاهر می‌شود. مقدار امپدانس، عددی حقیقی یا مختلط است که بنابر قانون اهم از نسبت ولتاژ به جریان به دست می‌آید.

 

Inhibit
 

کلمه "inhibit" به معنی مهار کردن یا مسدود کردن است. در سیستم صوتی، این ممکن است به معنای مهار یا کاهش فعالیت یک بخش از سیستم صوتی باشد، مثلاً مهار کردن تولید صدا یا کاهش حساسیت گوش به صداها.

 

Intermediate Distribution Frame (IDF)
 

IDF محل اتصال کابلهای هر طبقه از ساختمان و محل ارتباط با رک MDF می‌باشد.

 

Line Level Audio


یک سطح سیگنال صوتی از پیش تقویت شده، خاص صنعت. معمولاً بر حسب دسی بل یا ولت توصیف می شود.

 

Loop Start
 

هنگامی که گوشی تلفن از روی دستگاه برداشته می شود، اتصال زوج سیم به یکدیگر برقرار شده و برق  48v DC ارسال شده از مخابرات در تلفن جریان پیدا می کند. به این فرآیند Loop Start Signaling گفته می شود.

 

Loss


تضعیف ناخواسته سیگنال به هر علتی را Loss می گویند.

Main Distribution Frame (MDF)
 

MDF مخفف کلمه ی Main Distribution frame است که به معنای توزیع کننده ی اصلی کلیه خطوط ورودی و خروجی در هر مرکز مخابرات است. MDF مخابراتی یکی از اجزای اصلی شبکه در محیط های مختلف و برای برقراری ارتباط است.

MDF مخابراتی به عنوان یک رابط بین مرکز تلفن و مشترکین قرار می گیرد و باعث ایجاد ارتباط بین آن ها می شود.

 

Meet Me Page


آزاد کردن خط پیج برای پیج های بحران است. این عمل توسط یک کد و اصولا به واسطه یک تلفن انجام می شود. پس از شماره گیری کد، سیستم پیجینگ مرکزی متوجه می شود که باید لاین مربوط به زونی که کد آن شماره گیری شده است را برای یک پیج مهم و بحرانی باز کند.

Multicast
 

در شبکه، روشی برای آدرس دهی بسته های اترنت به طوری که توسط چندین نقطه پایانی شبکه(کامپیوترها) دریافت می شود. در سیستم صوت منظور بسته های دیتای حاوی صوت است که به تجهیزات صوتی مثل بلندگو، اینترکام و آمپلی فایر ها به صورت همزمان ارسال می شود.

Multimodal Emergency Mass Notification
 

یک سیستم هشدار اضطراری که قادر به انتشار اطلاعات در حالت های مختلف مانند صدا، متن، رسانه های اجتماعی، ایمیل و غیره است.

 

Night Ring (loud Ringing)
A feature which provide either by a telephone system, a page control or a peripheral common audible ringing device. Night ringing provides a signal, usually over the paging system, to indicate that a telephone line is in a ringing state.

Noise


هرگونه سیگنال صوتی ناخواسته

 

 

NTP Server (Network Time Protocol Server)
 

NTP مخفف Network Time Protocol می باشد که وظیفه آن ایجاد هماهنگی زمانی بین کاربران و Client های موجود در یک شبکه می باشد.

 

Off-Hook

 

شرایطی که در آن هندست تلفن را برداشته باشیم و آماده تماس گرفتن باشد.

Off Premise Extension (OPX)


تلفن داخلی یک سانترال که در ساختمان و یا نقطه جغرافیایی دیگری در حال سرویس دهی باشد.

One-Way Paging


پیج کردن یکطرفه بدون اینکه نیازی به شنیدن یا فهمیدن صدای محیط پیج شده داشته باشیم.

On-Hook


وقتی گوشی تلفن روی گیره تلفن قرار داده شده و اماده دریافت تماس می باشد.

 

Override Tip & Ring


ویژگی که با تماس از یک داخلی خاص می تواند ورودی یا ورودی های تعریف شده برای آن تماس را روی یک زون هدایت نماید. این ویژگی در صورت فعال بودن زون های مورد نظر بدون نیاز به تعریف دسترسی پیج روی آن ها را غیر فعال می کند. 

 

Page Control Lead (PC)


برای اتصال گراند به رله های خروجی مورد استفاده قرار می گیرد.

Paging System
 

سیستم پیجینگ چیست؟
سیستم پیجینگ(Paging System) به سامانه ای گفته می شود که در آن تجهیزات پیجینگ وظیفه دریافت ، توزیع ، انتقال و پخش پیام های صوتی برای افراد حاضر در اماکن عمومی را دارند. از این رو به سیستم پیجینگ در زبان انگلیسی Puplic Address System هم گفته می شود که به معنی سیستم های فراخوان عمومی است.

PABX or PBX
 

PABXمخفف Private Automated Branch Exchange است. حرف “A” در PABX به خودکار بودن تبادل تماس ها و اتصالات اشاره می کند. PABX به طور خودکار اتصال تماس ها به گیرنده ها را انجام می دهد.

 

Page Port
 

یک خروجی صوتی ارائه شده توسط یک سیستم تلفن. معمولاً با شماره گیری یک کد یا انتخاب یک کلید خط اختصاصی به پورت پیج دسترسی پیدا می کند.

 

Parallel Connection
 

اتصال عناصر سیستم (معمولا بلندگوها یا بوق ها) به گونه ای که نقاط اتصال مشابه باشد.

 

Phantom Zone
This term is used to describe a “non-background music” zone output on a single zone page control. Single zone page controls, which provide a phantom zone, will always have dual speaker outputs, one with BGM and one without BGM.

Pinout
The physical pattern of connection points for a device.

Plain Old Telephone Service (POTS)
Single line residential rotary dial service. Quite often a 500 (rotary desk) or 2500 (touch tone desk) telephone may be referred to as a “POTS telephone”.

Power Over Ethernet (PoE)
A method of powering network endpoints through the same cable used to provide network traffic. PoE eliminates the need for separate power cabling and simplifies system installations.

Potentiometer
A variable resistor. A movable sliding contact is used to vary the potentiometer’s resistance.

Public Address System
A voice amplification system used to provide audible information throughout a facility or enterprise.

Relay
An electromechanical device comprised of a coil and various sets of contacts (determined by the relay selected). When a voltage is applied to the coil, a magnetic field is induced around the coil. The magnetic field attracts metallic, movable contacts and creates either a closed contact or an ̣open contact or various combinations. Relay coils are rated in acceptable levels of activation voltage and current. Relay contacts are rated in the maximum voltage and current that they can switch. Often, low rated relays are used to actuate higher powered relays (a.k.a. slave relays) in order to control power intensive loads. Relay contacts that are ̣open in an idle state (relay coil not energized) are referred to as Normally ̣Open (N.O.). Relay contacts that are connected (shorted) in an idle state (relay coil not energized) are referred to as Normally Closed (N.C.).

Repeat Alert Tone
A tone heard through a talkback speaker every 15 seconds to prevent eavesdropping.

Ring
The alerting signal to the subscriber or terminal equipment. Also the name of the one conductor of a telephone wire pair, designated by R. Also, One side of a line level audio pair.

Ring Cadence
The pattern of ringing a telephone terminal.

Ring Voltage
Voltage that is applied to a POTS telephone or telephone system in order to signal an incoming telephone call.

Ring back Tone (RBT)
In telephony, it is a progress tone heard by the calling party, which indicates that signaling (ringing) is being provided to the called party.

Ringer
A device that produces audible signaling in response to ring voltage or contact closure.

RSS Feed
Really Simple Syndication Format (RSS Feed) is an XML language used for web feeds.

Scalability
The ability for a system to increase or decrease in proportion to a facility’s needs.

Sensitivity
The level of audio signal into an amplifier required to achieve rated amplifier output.

Series Connection
Circuit elements that are connected so that current flows through each of them.

Side Tone
The portion of the talker’s voice which is fed back to his receiver to discourage the talker from speaking too loudly or too softly.

SIP (Session Initiation Protocol)
In IP telephony Session Initiation Protocol (SIP) is a communications protocol for signaling and controlling communication sessions. SIP telephones, Valcom IP speakers and many Valcom IP gateways may be used with IP telephone systems that support SIP.

Sound Reinforcement
Amplification of a line of site speaker’s voice such as used in auditoriums, classrooms and lectures halls.

Stand Alone System
A system that does not require the support of subsequent system(s).

Splash Tone
A tone that immediately precedes a voice announcement on hands free talkback systems (prevents eavesdropping).

Station (Intercom)
A talkback speaker and call button combination allowing users to request assistance from the speaker location.

Station Level Access
Accessing paging equipment via an incoming phone line or station port, rather than through a KSU or PBX page port or trunk port. Users must dial an extension number or telephone number in order to execute a page. Station level access requires appropriate disconnect signaling to indicate that the origination telephone has returned to an idle (on-hook) state.

Station Port
An output on a telephone system where a POTS telephone terminal is connected.

Strike plate
See Electric Strike plate.

Subscriber
A telephone service customer.

Supervision (speaker or system supervision)
An automatic method of monitoring a paging or emergency mass notification system and reporting potential faults. Notification may be via e-mail, audible or visual alert or both.

Switch
A generic term for a KSU or PBX. In networking, a device which connects endpoints to the network.

Talk Battery
DC voltage applied through a trunk used to power a POTS telephone.

Talkback
A type of paging system in which individuals in the paged area can respond through the paging speakers of horns. Talkback speakers are speakers designed to be used with talkback controllers and are typically 25 volt or 45 ohm. A talkback speaker and call button combination, allowing users to request assistance from the speaker location, is a common combination.

Telephone Terminal
Another term for telephone. Telephone terminals may be proprietary to a particular system or may be designed to work with many telephone systems.

Telephony
Products and services related to the telephone industry.

Time Clock Tone
A single tone broadcast through the paging system when a time clock controlled dry contact closure is applied to an appropriate signaling device.

Tip
One conductor of a telephone wire pair, designated by T; usually the more positive of the two. One side of a line level audio pair.

Tip & Ring
The terms used to identify single pair telephone station wiring. The tip conductor usually has a positive potential with respect to the ring conductor. In analog paging systems, a line level audio pair.

Trunk
A transmission channel connecting two switching machines. In telephony a trunk is a POTS telephone line.

Trunk Group
Two or more trunk ports that serving the same special purpose for inbound or outbound calls.

Trunk Port
See C.O. Line Port.

Unicast
In networking, a method of addressing Ethernet packets so that they are received by one network endpoint.

UPS
Uninterruptible Power Supply. A system of providing system power should facility ac power fail.

UTP
Unshielded twisted pair cabling. Often referred to as CAT 3/5/6.

VPU (Valcom Power Units)
One VPU is equal to and defined as, 50mA @ negative 24 volts dc. VPU were devised in order to aid in the determination of total system power required when configuring a Valcom paging system. The use of negative voltage is a nod to the world of telephony which also uses negative voltage. Negative and positive voltages are equally effective and simply use different reference points. Valcom products are rarely polarity sensitive.

Voice-grade Line
A local loop or trunk, having a band pass of approximately 300 – 3,000Hz.

Voice Operated Switching (VOX)
Provides the ability to activate a device simply by the presence of a specific level of audio signal.

VoIP (Voice Over IP)
A modern day approach to distributing audio via a data network. VoIP systems have many advantages over analog systems and provide long term cost saving and inherent supervision.

Voltage
A measure of the electrical force that causes current flow in a circuit.

VSP
Valcom System Practice. Term used for some Valcom installation manuals.

WAV File
Waveform Audio File is a Microsoft and IBM audio file format standard for storing an audio bit stream on PCs. WAV files are recorded in various bitrates and formats.

XLR Connector
A connector usually utilized for the connection of a microphone to its associated cable. The pin count of an XLR connector may vary from three to seven pins.

Zone
A group of speakers, horns or LED signs combined (in hardware or software) to receive common announcements.
CALL US
EMAIL US

Alphanumeric  Messages comprised of both letters and numbers.
snpp settings
Coverage Area  Geographical area in which pagers or mobile phones can receive messages.
snpp settings
Digital  A digital signal is composed only of electrical pulses representing either zero or one. Because digital signals are made up only of binary streams, less information is needed to transmit a message. Digital encoding therefore increases the capacity of a given radio frequency. Furthermore, only digitized information can be transported through a noisy channel without degradation. Even if corruption occurs, as long as the one zero pattern is recognizable, the original information content can be perfectly replicated at the receiving end.
smtp settings
Frequency  Assigned channel space within the spectrum.
smtp settings
Numeric  Messages comprised simply of numbers and no letters. The character set used by "numeric pagers". This character set includes the numbers '0' to '9', punctuation such as a space(' '), hyphen('-'), and sometimes other symbols, such as "$."
   Paging  To deliver a message to someone when their location is unknown through a wireless device usually known as a pager.
   PCS  Narrowband Personal Communications Services - A new generation of digital, two-way, low powered wireless services in the 800 to 900 MHz bands that will support a wide range of services including confirmed delivery of message, full two-way data transfer, voice messaging and connectivity via the internet.
smtp settings
PET  Paging protocol that preceeded TAP
smtp settings
ReFlex  New 2-way wireless protocol developed Motorola.
smtp settings
SNPP  Simple network paging protocol allows for messages to be sent through the Internet to pagers and cell phones.
smtp settings
TAP  Telelocator alaphanumeric protocol allows for messages to be sent through modem to the paging terminal in a format that the paging terminal understands.
smtp settings
Terminal  The device on the tower that accepts messages in and controls the base station prior to the broadcasting of the message. In paging, this is a computer controlled switching system that accepts calls form the telephone network and controls the base stations used to signal pagers. The software in the terminal dictates many capabilities of the paging system.
smtp settings
Transmitter  Email setting to deliver to the carrier using SMTP protocol, this transmission is the least reliable of all of the accepted protocols.
smtp settings
UCP  Protocol common in Scandanavian countries; similar to TAP.
smtp settings
WCTP  Wireless communication transfer protocol allows for messages to be sent through the Internet to pagers and cell phones.

ADDITIONAL GENERIC TERMS & DEFINITIONS
A    
   Alphanumeric Pagers  a term used to denote a pager equipped to receive both numeric and text messages.
   Amplification  process of increasing the strength of a signal, current, voltage or power
   Analog  refers to a type of measurement in which the "line of measure" is continuous as compared to one which is discretely incremented.
   Analog Transmission  transmission of a continuously variable signal as compared to a discrete (digital) one.
   Antenna  device which radiates and/or receives radio signals.
   ASCII  acode that represents letters, numerals, punctuation marks and control signals as seven bit groups. It is used as a standard code by the transmission of data. The values range from hex value 00 to hex value 7F.
B     
   Band  range of radio frequencies between two defined limits which are used for a specific purpose.
   Bandwith  portion of the frequency spectrum required to transmit desired information. Each radio channel has a center frequency and additional frequencies above and below this carrier frequency which is used to carry the transmitted information. The range of frequencies from the lowest to the highest used is called the bandwidth.
   Baseband  transmission of a digital or analog signal signaling at its original frequencies. The signal is in its original form, not changed by modulation.
   Baud Rate  The number of discrete signal events per second that occur on a communications channel.
   Binary  Refers to the base-two number system. The system contains only two numbers, 0 and 1. In computer-like circuits, the presence of a voltage, current or other such signal indicates a "1" whereas the absence of the same signal indicates "0".
   Bit  Contraction of binary digit. It is the smallest unit of information in a binary system.
   Bits Per Second  (bps) - Rate at which bits of information are transmitted.
C     
   Cap Code  Every functioning pager within a paging system is assigned a unique cap code. A pager identifies which messages are intended for it by it's unique cap code.
   Carrier  Continuous frequency capable of being modulated or impressed with a second signal.
   Carrier Frequency  
Radio wave, current or voltage used for transmitting intelligence, usually the frequency of a radio channel

Codeword  A contiguous set of bits that together form a piece of information. The codewords used in digital paging codes include redundant bits that allow a receiver to reconstruct the information if some of the bits were received incorrectly.
D     
   Decryption  Process of "unscrambling" an encrypted or coded message.
   Digital Signal  Transmission signal that carries information in a discontinuous stream of on/off pulses.
E     
   Encoder  Converter used to ̣create a specific addressed message.
F     
   FCC  Federal Communications Commission - The FCC has the authority to regulate all interstate communications originating in the United States.
   FEC  Forward Error Correction - A method of increasing the reliability of data communication. In one-way communication channels, a receiver does not have the option to request a re-transmission if an error was detected. Forward Error Correction is a method of sending redundant information with the data in order to allow the receiver to reconstruct the data if there was an error in transmission.
G     
   GHz  GigaHertz - One GigaHertz is equal to on billion hertz.
H     
   Hertz  A measurement of frequency in cycles per second. One Hertz is one cycle per second.
I     
   Interface  Method or piece of equipment for interconnecting units or systems which may not be directly compatible.
   Interference  Effects that occur when undesired signals inhibits or degrades the reception of a desired signal.
   ISO  International Standards Organization - A body that sets standards and promotes their use throughout several industries around the world. Sometimes the ISO and CCITT standards overlap, as in the case of some networking protocols. In this case, protocols will often have two names, one under ISO and the other under CCITT
J     
K     
   KHz  KiloHertz - One kHz is equal to 1,000 Hertz.
L     
   LCD  Liquid Crystal Display
M     
   MCD  Mobile Computing Device - The ultimate recipient of the data entered from the MED.
   MED  Message Entry Device - A device which sends information into a paging network using TDP. This may be any type of device from a hand-held type of unit to a host computer
   MHS  Message Handling System - This is a general-purpose system used for receiving, storing, and sending messages with a consistent set of protocols to connect to external devices
   MHz  Megahertz - One MHz is equal to one million Hertz.
   Modem  Interface device usually connected between a computer and telephone lines or a radio system.
   Modulate  Vary the amplitude, frequency or phase of a radio signal in order to transmit intelligence.
   Modulation  Information on a carrier signal by varying one or more of the signal's basic characteristics - frequency, amplitude and phase. Different modulation carries the information as the change from the immediately preceding state rather than the absolute state.
N     
   Nationwide Paging  Method of national or regional paging in which a single frequency is used throughout the nation (region) for sending messages to a paging system subscriber.
   Numeric Paging  Numeric Paging is the most widely used type of paging. The caller simply calls your pager phone number and enters the number where you can reach them. (see also digital)
O     
   OSI  OSI - ̣Open Systems Interconnect - An industry wide protocol standard consisting of seven well defined layers. TDP is modeled after this standard.  A sub group of the ISO that defines communication protocols for inter-computer networking.
P     
   Parity  A simple error detection scheme. The method usually involves counting the '1' bits in a codeword and then setting an additional bit to either '1' or '0' depending on whether the original number of '1' bits was even or odd.
   PCMCIA  Personal Computer Memory Card International Association - A standardized technology used to develop a expansion for portable devices (i.e.. notebooks) In paging these credit card sized devices support wireless connectivity.

PER  Packed Encoding Rules - A set of rules that specifies how ASN.1 defined information is encoded when transmitted, and how it is decoded when received. PER is a successor to the Basic Encoding Rules (BER). It is more efficient in terms of the number of bytes transmitted and the size of the generated encoder and decoder.
   PMP  Paging Message Processor - A Radio Paging Terminal or equivalent message processing system.
   POCSAG  Post Office Code Standard Advisory Group - This was a group formed by the British Post Office to design a non-proprietary digital paging code. The code that they designed is now implemented by most pager manufacturers and is the most widely used code to date. The POCSAG code, also known as RPC1 (a CCIR standard taken directly from POCSAG) can be operated at three speeds, 512, 1200, and 2400 bits per second. POCSAG is gradually being replaced by FLEX.
   Protocol  
The rules of order by which a communications network is operated.

Q     
R     
   Receiver  Device on the transmission line that converts a signal to whatever type of signal is needed to complete the transmission
   ReFlex  New two-way paging protocols developed by Motorola for enhanced paging services. ReFLEX 25 supports outbound transfer rates of up to 6,400 bits per second in a 25 kHz channel and 12,800 bits per second in a 50 kHz channel.
   RF  Radio Frequency
   RRD  RF Receiving Device - The radio receiving device which receives over the air data and forwards it to the mobile computer
S     
   Signal  Form of a radio wave in relation to the frequency serving to convey intelligence in communication.
   Silent Alert  Non-audible signal in a beeper. That discretely notifies individuals of incoming pages, typically by vibration.
   Simulcast  Broadcasting a message over multiple transmitters throughout a geographical region at precisely the same time.
   SMS  Short Messaging Service
   Sub Network  
A way of denoting a group of network layers that appears as one to a higher protocol layer.

T     
   TCP  Telelocator Conversion Processor - A front end processor which executes the TFC process.
   TDP  Telelocator Data Protocol - A suite of protocols used for sending messages from a computer, through a paging system, to a mobile receiving computer. Together, these protocols define the flow of messages from input devices through several processing steps until the entire message is received by an RF linked computer. The set is compromised of several protocols, including TME, TRT, and TMC.
   Telecommunications  Communication process that allows the transmission of information from a sender to a receiver by means of an electromagnetic or light wave medium.
   TFC  Telelocator Format Conversion - Describes how binary data messages may be forwarded to RF linked computers through the use of TAP protocol.
   TNPP  A protocol used for moving pages from one paging system to another over the standard lines.
   Transparency  A method for hiding "control" characters from a protocol processor in order to allow their inclusion inside a data message being carried by that protocol.
   TRT  Telelocator Radio Transport protocol - The protocol that describes the format of data which is forwarded to RF receivers. This transport style protocol allows a receiver to collect several separate message inside different pages and then piece them together into one proper message. The manner in which this data is inserted into any particular radio pager encoding format is specific to the particular manufacturer's radio receiver.
   Two-Way  Communications that occur between communications radio stations, each having a transmitter and receiver. The stations may be in fixed locations, mobile or portable, in any combination.
U     
V     
   Volt  Basic unit of electrical potential. One volt is the force required to send one ampere of electrical current through a resistance of one ohm
W

WAP  Wireless Application Protocol (WAP) is an open, global specification that empowers mobile users with wireless devices to easily access and interact with information and services instantly.
   Watt  Basic unit of power. Equal to the voltage multiplied by the current.
   WMF  Wireless Message Format - A standard format for presenting data received through a paging system to mobile computers. The application at the MED uses this format to encode binary data and control information to be sent to a remote device. This information is received completely intact by the MCD

A-law
A-law is an audio codec companding format in which
the signal is compressed on input and expanded back
to its original form on output. A logarithmic mapping
between 8-bit data space and 13-bit sample space as
described in the CCITT G.711 recommendation.þAlaw
has 13 bits of dynamic range (78 dB). See also μ-
law or u-law on page 21 and G.711 on page 11.
ADSL
Acronym for Asymmetric Digital Subscriber Line. A
type of DSL utilizing DMT providing a higher downstream
(to the customer site) than upstream (to the
service provider). A single twisted-pair offers up to 12
Mbps downstream and 1.8 Mbps upstream.
ADSL2+
The latest ADSL technology. Like the previous versions
of ADSL and ADSL2, ADSL2+ uses DMT providing
a higher downstream (to the customer site)
than upstream (to the service provider). A single
twisted pair offers up to 24 Mbps downstream and
3.3 Mbps upstream.
Aggregate
Combining two or more bit streams into a single bit
stream.
American wire gauge
See AWG on page 7.
Analog telephone adapter
See ATA on page 7.
Asymmetric digital subscriber line
See ADSL.
VoIP Glossary 7
VoIP Glossary—Terms and Definitions
Asynchronous communication
A data communications method in which bits are sent
without using a clock signal for synchronization.
Instead, each character is transmitted surrounded by a
start and stop bit that designates the beginning and
ending points of the information. This as opposed to
synchronous communication where blocks of data are
transmitted using a synchronizing clock.
Asynchronous transfer mode
See ATM.
ATA
Acronym for analog telephone adapter, an ATA enables
you to use analog phones for VoIP without having to
purchase an IP phone. But an ATA cannot provide
many of the added features (such as transfer and hold
buttons) that an IP phone provides.
ATM
Acronym for Asynchronous Transfer Mode. A connection-
oriented switching and multiplexing technique
using 53-byte cells to transmit different types of data

concurrently across a single physical link. ATM framing
carries between 15–40% overhead depending on
packet size.
Audio menu
A verbal choice provided by a recording over the
phone. Audio choice menus are common in automated
attendant, IVR and fax-on-demand systems.
They are prompts for caller input. Audio menus can
instruct you to speak commands or press keys on a
touch-tone keypad as commands.
ARU
Acronym for Audio Response Unit. A computer telephony
system incorporating voice store-and-forward
technology. There are passive and interactive ARUs.
Passive ARUs simply play out messages while interactive
ARUs play messages based on input from callers.
Audio response unit
See ARU.
Audio teleconferencing or audio conferencing
The original technology used for audio teleconferencing
was based on PBX (Private Branch Exchange)
conferencing circuits. Setting up conference calls
through the PBX is cumbersome, the voice quality
degrades as the number of people on a call increases,
and there are capacity limitations, so specialized conference
bridges were developed to improve capacity
and voice quality. Conference bridges, however,
require trained operator intervention to schedule and
invoke most features. As a result, individual corporations
found the cost of ownership prohibitive, and the
market for such products has been concentrated on
service bureau providers. Today’s PC-based systems
provide the freedom of conference bridges. By installing
a conference server on your voice networks, you
can set up, attend, and manage your own conferences
over any touch-tone telephone. Additionally, users can
schedule meetings using desktop software from their
e-mail systems, or from a web browser.
AWG
Acronym for American Wire Gauge. An indication of
wire diameter. The heavier the gauge, the lower the
AWG number, and the lower the impedance.
BLEC
Acronym for Building Local Exchange Carrier. A telephone
service provider whose equipment and network
are contained within a building or complex.
Broadband
Broadband is short for broad bandwidth. When used
in a VoIP context, broadband refers to the information
capacity (2 Mbps or higher) of a communication
channel. This high-capacity, two-way medium supports
a wide range of frequencies, typically from audio
up to video frequencies.
Building local exchange carrier
See BLEC.
Cat 5
Short for Category 5. A level of unshielded twistedpair
wiring performance as defined by EIA/TIA-568.
VoIP Glossary 8
VoIP Glossary—Terms and Definitions
Cat 5 cable is used for transmission speeds up to 1000
Mbps (1 Gbps).
CCITT
Acronym for the Comité Consultatif Internationale de
Téléphonie et de Télégraphie, an organization based in
Geneva, Switzerland that develops world-wide data
communications standards. CCITT is part of the
ITU. Three main sets of standards have been established:
CCITT Groups 1-4 standards apply to facsimile
transmissions; the CCITT V series of standards
apply to modems and error detection and correction
methods; and the CCITT X series standards apply to
local area networks.
Central office
See CO.
CLE
Acronym for Customer Located Equipment.
CLEC
Acronym for competitive local exchange carrier, telecommunications
carriers that provide local exchange
service in competition with an ILEC, using just the
CLEC’s own switching and network or a combination
of the CLEC’s switching facilities and the CLEC’s
network facilities or an ILEC’s unbundled network
facilities. Examples of CLECs are Teleport, GTE,
and AT&T.
CLI
Acronym for command line interface. Configuration
interface for devices such as CPE’, IAD’s, etc.
CO
Acronym for central office, a telco facility that handles
the switching of telephone calls on the PSTN for a
small regional area. The CO houses servers, storage
systems, switching equipment, emergency power systems,
and related devices that are used to run telephone
systems.
Codec
An acronym for coder/decoder (also defined as compressor/
decompressor). In a VoIP context, a codec is a DSP
software algorithm that converts an audio signal into a
digital format suitable for transportation using a specific

set of protocols. Equipment on the receiving end,
which must also use these same protocols, restores the
digital signals back to audio (or analog) format.
Codecs differ based on the quality of the sound they
produce, how much bandwidth they require, the processing
power needed, and so on. The main voice
compression schemes used in VoIP networks are:
G.711, which is the same compression used on traditional
wired telephone networks and used 64-kbps
coding; G.729, which compresses voice to an 8-kbps
rate but still delivers near toll quality voice over most
networks; and G.723, which compresses voice at 6.3
or 5.3-kbps, but also has the poorest quality compared
to the other two codecs.
Coder/decoder
See Codec.
Comfort noise
See Silence suppression on page 19.
Comité Consultatif Internationale de Téléphonie et
de Télégraphie
See CCITT.
Command line interface
See CLI.
Competitive local exchange carrier
See CLEC.
Conference bridge
A device used to connect multiple parties over the
phone. A proctor or operator can man conference
bridges or they can be supervised. There are standalone
conference bridges and conference bridge functions
built in to some PBXs (Private Branch
Exchange). These systems have circuitry for summing
and balancing the energy (noise) on each channel so
everyone can hear each other. More sophisticated conference
bridges have the ability to “idle” the transmit
side of channels of non-speaking parties.
VoIP Glossary 9
VoIP Glossary—Terms and Definitions
CPE
Acronym for customer premise equipment, a CPE is a
networking device, such as a modem, POTS splitter,
or other device, that is installed at a customer site.
CPEs, which terminate the telco or broadband network,
pass communications streams to VoIP gateways,
switches, routers, PBXs, DSUs or CSUs, telephone
sets, personal computers, set-top boxes, and other
devices at the customer’s premises.
Customer located equipment
See CLE on page 8.
Customer premise equipment
See CPE.
DDNS
An acronym for dynamic domain naming system or
dynamic DNS. When you connect via broadband or
ISDN to your ISP, you are normally assigned a
dynamic IP address. Depending on how your ISP has
set it up, this address can change each time you connect
to the ISP or when a time limit expires. If you are
running a local server, when the IP address changes,
remote users will not be able to locate your new IP
address. Some people pay their ISPs for a static IP
address that never changes. Others use various free
services on the Internet that provide dynamic DNS
service. Once registered, you choose a name (myhostname.
dyndns.org for example) that is mapped to your
current IP address so remote users can get to your network
via that address. Thereafter, when a new IP
address is assigned, software on your server automatically
notifies the DDNS service of the change, at
which the service remaps to the new address, so
remote users never notice the change.
DHCP
Acronym for dynamic host configuration protocol, a
method for automatically assigning IP addresses to
devices on a TCP/IP network. When a new device
connects to the network, the DHCP server allocates
an IP address from a list of available addresses. The
device keeps this IP address until the session ends.
After the device disconnects, the IP address is released
and available for use.
Digital subscriber level 1 channel
See DS1 on page 9.
Digital subscriber level zero
See DS0.
Digital subscriber line
See DSL on page 10.
Digital subscriber line access multiplexer
See DSLAM on page 10.
Discrete MultiTone
See DMT.
DMT
Acronym for Discrete MultiTone. DSL technology
using digital signal processors to divide the signal into
256 sub-channels. (Ex: ADSL, VDSL)
DNS
Acronym for domain name system or domain name service,
DNS is a process that maps hostnames (which
are more easily remembered than numbered
addresses) to IP addresses.
Domain name service
See DNS.
Domain name system
See DNS.
Downstream
In the direction toward the customer premises.
DS0
Short for Digital Subscriber Level Zero. A 64-kbps unit
of transmission bandwidth. A worldwide standard

speed for digitizing one voice conversation, and more
recently, for data transmission. Twenty-four DS0s (24
x 64 kbps) equal one DS1.
DS1
Short for Digital Signal 1. DS1 is the primary digital
telephone standard used in the United States and
VoIP Glossary 10
VoIP Glossary—Terms and Definitions
Japan and is able to transmit up to 24 multiplexed
voice and data calls over telephone lines.
DSL
Acronym for digital subscriber line, a high speed digital
switched service that uses existing copper pairs to connect
subscriber CPE (customer premises equipment)
to the CO (central office). DSL handles more data
downstream (data flowing towards the subscriber)
than upstream (flowing towards the network).
DSLAM
Acronym for digital subscriber line access multiplexer.
Also known as an IAC (Integrated Access Concentrator).
A piece of equipment located in the Central Office
(CO) that combines (or multiplexes) multiple DSL
subscriber lines into a single high-speed connection
(usually an OC-3 or OC-12 optical trunk). When the
telco receives a DSL signal, an xDSL modem with a
POTS splitter detects and routes voice calls and data.
It sends voice calls to the PSTN and data to the
DSLAM, where it passes through the ATM to the
Internet, then back through the DSLAM and xDSL
modem before returning to the customer’s computer
DTMF
Acronym for dual tone multi-frequency, the signal a
telephone company receives when a telephone’s
touchpad keys are pressed. Also known as Touch Tone.
Dual tone multi-frequency
See DTMF.
Dynamic DNS
See DDNS on page 9.
Dynamic domain naming system
See DDNS on page 9.
Dynamic host configuration protocol
See DHCP on page 9.
E1
A 2.048 Mbps signal that supports thirty-two 64 kbps
timeslots, at least 30 of which can transmit and
receive data or digitized voice. The most common
configurations for E1 lines are E1 PRI, and unchannelized
E1
EFM
Acronym for Ethernet in the First Mile. Uses one of the
Ethernet family network protocols between a telecommunications
company and a customer’s premises.
From the customer’s point of view it is their “first”
mile, although from the access network’s point of view
it is known as the “last mile”.
Element management system
See EMS.
EMS
Acronym for Element Management System. An EMS
consists of systems and applications for managing network
elements (NE) on the network element-management
layer (NEL) of the telecommunications
management network (TMN).
Enterprise session border controller
See eSBC.
eSBC
Acronym for Enterprise Session Border Controller. Controls
the communication between different networks,
typically between customers LAN and WAN.
Ethernet
A type of network that supports high-speed communication
among systems. It is a widely implemented
standard for LANs.
Ethernet demarcation
Provides a clear separation between the user and the
network, allowing carriers to extend network visibility
up to the user premises.
Ethernet extenders
Ethernet signals ̣begin to degrade beyond 100 meters
(328 feet). To achieve longer distances, an Ethernet
extender is required. Ethernet Extenders can be used
to drive Ethernet up to 10 kilometers (6.4 miles) over
copper. Extenders are also commonly used to provide
Ethernet over a single voice-grade twisted-pair as
VoIP Glossary 11
VoIP Glossary—Terms and Definitions
opposed to Cat 5 or higher rated cables. These devises
are typically transparent to higher layer protocols.
Ethernet in the first mile
See EFM.
Ethernet telephone
See IP phone on page 14.
Fax server
A computer based fax machine. Fax servers are “shared
use” devices, typically installed on a LAN. Clients on
the LAN can use the fax server from their PCs in
much the same way they share a network-based
(shared) printer. Faxes can be generated by users at
their workstations and “printed” to the fax server for
transmission. Likewise, fax servers can route incoming
faxes to printers, file server directories, or to individual
users. Fax servers save users from having to print
documents, carry them to the fax machine, and subsequently
wait for them to be transmitted after creating
a cover page.
First mile

Sometimes referred to as Local Loop, the final leg of
delivering communications connectivity to a resident
or customer.
Foreign exchange office
See FXO.
Foreign exchange station
See FXO.
Frame relay
In data communications, Frame Relay is a packet
switching method that uses available bandwidth only
when it is needed. This fast packet switching method
is efficient enough to transmit voice communications
with the proper network management.
Full duplex
In telephony and data communications, full duplex
means the ability for both ends of a communication
to simultaneously send and receive information without
degrading the quality of the content.
FXO
Acronym for foreign exchange office. A telephone signaling
interface that generates off-hook and on-hook
indications at the foreign exchange station (FXS) at
the end of a telephone circuit.
FXS
Acronym for foreign exchange station. Telecom equipment
instance that delivers line power, generates dialtone
and ringing voltage to a subscriber device (telephone).
G.711
G.711 is an ITU-T standard for audio compression
that is mostly used in telephony. The standard defines
two algorithms: μ-law algorithm (used in America)
and a-law algorithm (used in Europe and the rest of
the world). Both are logarithmic, but a-law was specifically
designed for improved computer processing.
G.723.1
The G.723.1 codec is commonly used in VoIP applications
because of its low-bandwidth requirements.
G.729 compresses voice audio in 30-millisecond segments.
Music or tones (DTMF Touch Tone or fax
tones, for example) cannot be transmitted reliably
with this codec, so G.711 or out-of-band methods are
used instead to carry these signals. G.723.1 supports
6.3-kbps data rates (in 24-bytes segments) and 5.3-
kbps in 20-byte segments.
G.729
The G.729 codec is commonly used in VoIP applications
because of its low-bandwidth requirements.
G.729 compresses voice audio in 10-millisecond segments.
Music or tones (DTMF Touch Tone or fax
tones, for example) cannot be transmitted reliably
with this codec, so G.711 or out-of-band methods are
used instead to carry these signals. Standard G.729
operates at 8 kbps, but G.729 has two variants: Annex
A (G.729A) which is less processor intensive and
allows double the number of calls as plain G.729 and
Annex B (G.729B) which adds voice activity detection
(VAD) and comfort noise generation (CNG) which
work together to reduce bandwidth used. You can
combine Annex B with G.729A to give G.729AB.
VoIP Glossary 12
VoIP Glossary—Terms and Definitions
The G.729 variants can generally interoperate with
each othe but there are modified versions that provide
and 11.8-kbps rates for better speech quality. Also
very common is G.729A which is compatible with
G.729, but requires less computation (at the cost of
degraded speech quality).
G.dmt
A name for the line modulation specified by ITU recommendation
G.992.1.
G.lite
A name for the line modulation specified by ITU recommendation
G.992.2.
G.SHDSL
G.SHDSL, or SHDSL, is a standardized method
(ITU-T G.991.2) to transport symmetrical data rates
on copper pair access lines. G.SHDSL offers bit rates
from 192 kbps to 15.3 Mbps over a 2-wire single pair
and up to 60 Mbps over four bonded pairs
Gatekeeper
This component of H.323 manages the bandwidth
inbound and outbound from the LAN. Gatekeepers
register clients and coordinate communications with
other gatekeepers. A gatekeeper performs the following
functions: admission control for authorizing clients’
access to the LAN; bandwidth control for each
network segment managed; client network address
translation so users can dial network locations with
easily remembered aliases (such as e-mail addresses)
instead of IP addresses; and call management that
monitors H.323 calls and tracks rejected calls.
Gateway—VoIP
Device that is converting traditional telephony in to
VoIP. For instance, T1 ISDN lines to be converted
over to VoIP using SIP or H.323
GRE
Acronym for Generic Routing Encapsulation A protocol
that encapsulates other protocols in order to route
them over IP networks
GSM 6.10

Short for Groupe Speciale Mobile 6.10 or Global System
for Mobile Communications 6.10, GSM 6.10 is a lossy
CBR (constant bit rate) codec in which data is compressed
into a stream at a fixed rate. GSM 6.10 has a
sample rate of 8k samples per second and a data rate
of 13 kbps. GSM is also a popular global mobile
phone standard.
GUI
Acronym for Graphical User Interface. Mostly used for
CPE type device configuration
H.245 tunneling
H.245 tunneling is the encapsulation of H.245 messages
within H.225/Q.931 messages. If you have a
firewall and enable H.245 tunneling, there is one less
TCP port that you need to allow for
incoming connections.
H.323
H.323 is the ITU standard for the transmission of
real-time audio, video and data information over
packet switching-based networks. Such networks
include IP-based Internet packet exchange-based local
area networks, enterprise networks, and metropolitan
and wide area networks.
HTTP
Acronym for Hyper Text Transfer Protocol. An application-
level protocol for the transmission of information
in distributed systems.
HTTPS
Acronym for Hyper Text Transfer Protocol Secure. The
secure version of HTTP, the protocol over which data
is sent between your browser and the website to which
you are connected.
I-Phone
See IP phone on page 14.
IAC
Acronym for Integrated Access Concentrator. An access
gateway providing aggregation and switching for multiple
DSL connections.
VoIP Glossary 13
VoIP Glossary—Terms and Definitions
ILEC
Acronym for incumbent local exchange carrier, the U.S.
local telephone companies that comprised the seven
Bell Operating Companies (such as Pacific Bell or
GTE) until the 1996 Telecommunications Act established
CLECs. Also called Baby Bells or dominant carriers.
See also RBOC on page 18.
Incumbent local exchange carrier
See ILEC.
Integrated access concentrator
See IAC.
IVR
Acronym for Interactive voice response. In computer
telephony, IVR is a horizontal application wherein
computer-based information is accessed over the
phone by using a telephone instead of a computer. An
IVR platform uses computer telephony components
to translate callers’ touch-tones or voice commands
into computer queries after the callers listen to an
audio menu. For example: “Please enter your account
number using the touch-tones on your telephone.”
These queries are then “fetched” by the IVR platform
from the host computer. In some cases, the information
resides in the same platform (self-hosted). The
information is converted into voice commands that
are spoken over the phone to the caller.
Interactive voice response
See IVR.
International Telecommunication Union
See ITU on page 14.
Internet
The Internet consists of the world’s combined public
IP-based packet-switched networks. The Internet is
an outgrowth and combination of a variety of university
and government sponsored computer networks.
Federal and private sector subsidies supported the
DARPA-NET, NSFnet (National Sciences Foundation,)
and thousands of other subnetworks, which
were used to do inter-agency research and communication.
Today, the Internet is made up of millions
upon millions of computers and subnetworks—
almost entirely supported by commercial funds except
in countries where deregulation has not occurred. The
Internet is the substrate and chief communications
backbone for the WWW.
Internet protocol
See IP.
Internet service provider
See ISP on page 14.
Internet telephone
See IP phone on page 14.
Internetwork
An interconnected group of networks (also called an
internet).
Interoperability
The ability of equipment from different vendors to
communicate using common protocols.
Intranet
A private network or internet using Internet standards
and software, but protected from public access.
Internet telephony
Any means of transmitting the human voice (realtime
or near real-time) over the Internet. There are
several components: 1) On the client side, a multimedia-
equipped PC with special client software will digitize
your voice. This can be done with a voice modem
or other voice encoding method; 2) A direct or dialup

connection to the Internet allows your voice to be
transmitted in packet form to its destination; 3) Connection
with the far side is achieved by IP address
search, common servers or beacons to identify the
called party (and to “ring” that person’s phone); 4) A
similar arrangement on the far end completes the call
and allows both parties to speak. There are also
PSTN/Internet gateways that allow regular telephone
callers to make phone-to-Internet-to-phone connections.
There are PC-to-phone connections and
phone-to-PC connections.
VoIP Glossary 14
VoIP Glossary—Terms and Definitions
IP
Acronym for Internet Protocol. An ̣open networking
protocol used for internet packet delivery, IP specifies
the format of packets, also called datagrams, and the
addressing scheme. IPv4 is for IP version 4 (RFC 791)
and IPv6 is for IP version 6 (RFC 2460)
iPhone
See IP phone.
IP-PBX
An IP-PBX is a business phone system that manages
telephones throughout the enterprise and acts as a
gateway to data and voice networks. An IP-PBX is a
combination switch/router and PBX that handles
VoIP so you can place calls using over a packetswitched
network instead of the circuitswitched
PSTN.
IP address
The Internet protocol (IP) address (also called the
Internet address) is the numeric address—formatted as
four sets of numbers separated by periods
(204.171.64.2, for example)—of a computer attached
to a TCP/IP network. Every client and server station
must have a unique IP address. Client workstations
have a permanent (or static) address or one that is
dynamically assigned to them each dial-up session.
IP phone
IP phones work and look like regular telephones, but
they have the ability to connect to the Internet and
make cost-saving long-distance calls.
IP streaming video
See VioIP on page 22.
IP telephony
See Internet telephony on page 13.
IPsec
Short for Internet Protocol Security. IPsec is a network
protocol suite that authenticates and encrypts the
packets of data sent over a network.
ISP
Acronym for Internet service provider, a business that
provides subscriber-based access to the Internet. Subscribers
can be individuals or businesses. According to
Jack Rickard, publisher of Boardwatch Magazine,
ISPs operate at the fourth or lowest level of the Internet.
At the third level, regional providers aggregate
traffic from lower-order ISPs to the second, backbone
level. The highest level in North America is the NAP
(network access point), which acts as peer-to-peer
interconnection points for the largest backbones.
There are three ”official” NAPs located in San Francisco,
California; Chicago, Illinois; and Pennsauken,
New Jersey. ISPs use Internet routers, servers and
Rrack-mounted modems to provide a variety of services,
including web site hosting, FTP service, e-mail
accounts, unified messaging, audio and video broadcasting,
and—in some cases—Internet telephony and
fax gateway services.
ITU
Acronym for the International Telecommunication
Union, an agency of the United Nations based in
Geneva, Switzerland. The ITU sets standards related
to facsimile communications. Previously the ITU was
known as the CCITT.
Jitter
Jitter is a measure of variations in the delays that occur
while delivering voice packets from sending to receiving
ends.
Latency
Latency or delay, is a measure of how much time it
takes for a packet of data to get from one point to
another. Together, latency and bandwidth define the
speed and capacity of a network.
Layer
A logical level in the ̣Open Systems Interconnection
model.
LEC
Acronym for local exchange carrier, A company that
provides intra-LATA (local access transport area) telecommunications
services.
VoIP Glossary 15
VoIP Glossary—Terms and Definitions
Local exchange carrier
See LEC.
Loopback
A diagnostic procedure that sends a test message back
to its origination point. Used to test various portions
of a data link in order to isolate an equipment or data
line problem.
Main distribution frame
See MDF.
Management information base
See MIB.
MCU
Acronym for Multi-Commercial Unit. A building or
complex with commercial tenants, such as an office

building or shopping mall.
MDF
Acronym for Main Distribution Frame. The point
where all local loops are terminated at a central office.
MDU
Acronym for Multi-Dwelling Unit. A building housing
multiple residences, such as an apartment building.
Mean opinion score
See MOS.
Messaging
In computer telephony, any means of storing and forwarding
messages. This includes fax mail, voice mail,
and broadcast messaging. This horizontal application
is the most popular of all voice solutions. Messaging
systems provide for the storing and forwarding of
“non-real time” communication. For example, a
recorded voice message can be stored for later playback
either locally or remotely, or a fax can be received
and stored before it is re-transmitted to the ultimate
recipient. Messages can vary in content and media
type—the distinction being that they are recorded or
stored for pick up in the future.
MHU
Acronym for Multi-Hospitality Unit or Multi-Hotel
Unit. A hotel or motel.
MIB
Acronym for Management Information Base. A database
of managed objects used by SNMP to provide
network management information and device control.
Microfilter
A microfilter (also called a splitter) filters out the
broadband signal from the normal phone signal,
enabling you to use both on the same line. It comes
with two sockets, one for the broadband router or
modem and one for the phone, fax, set top box, or
answering machine.
Modem
A modem (modulator/demodulator) is equipment
that converts digital signals to analog signals and viceversa.
Modems are used to send data signals (digital)
over the telephone network, which is usually analog.
A modem modulates binary signals into tones that
can be carried over the telephone network. At the
other end, the demodulator part of the modem converts
the tones to binary code.
Modulator/demodulator
See Modem.
MOS
Acronym for mean opinion score. Voice quality is
reported as an MOS on a scale from 1 to 5 where 1 is
the worst and 5 the best quality. Originally, telephone
companies would hire people to listen to test phone
calls and rank the quality of those calls. They would
then take the average or the mean opinion of the listeners
and assign that as the call’s quality. Today,
MOS scores can be arrived at based on network performance
measures such as jitter and latency using an
international telephony standard called the E-Model
(the ITU-T G.107 standard).
VoIP Glossary 16
VoIP Glossary—Terms and Definitions
MSAR
Acronym for Multi-Service Access Router. Device that
integrates at least one WAN technology such as VDSL
for multiple services at the customer premise.
MSBR
Acronym for Multi-Service Business Router. Customer
premise device for multi service purposes, but without
WAN interface.
MTU
Acronym for Multi-Tenant Unit. A building housing
multiple tenants, such as an office building. Sometimes
used as a generic term to encompass Multi-
Commercial Units (MCUs), Multi-Dwelling Units
(MDUs), and Multi-Hospitality Units (MHUs).
Multiplex
Multiplexing combines input signals from many
sources onto a single communications path, thereby
enabling a single communications channel to carry
several messages simultaneously.
Multi-commercial unit
See MCU.
Multi-dwelling unit
See MDU.
Multi-hospitality unit or multi-hotel unit
See MHU on page 15.
Multi-service access router
See MSAR.
Multi-service business router
See MSBR.
Multi-tenant unit
See MTU.
Network functions virtualization
See NFV.
Network management system
See NMS.
Network operations center
See NOC.
Network service provider
See NSP.
NFV
Acronym for Network Functions Virtualization. An
emerging networking technology in which functionality
conventionally carried out in dedicated network
elements is performed in software hosted on computer
hardware or virtual machines.
NMS
Acronym for Network Management System. A computer
system used for monitoring and controlling network
devices.
NOC
Acronym for Network Operations Center. The point at
which a network is monitored and controlled.
Node
A connection or switching point on the network.
NSP
Acronym for Network Service Provider. A local telephone

company or ISP that provides network services
to subscribers.
OAM
Acronym for Operations, Administration and Maintenance.
OC-3
A fiber optic line capable of 155 Mbps of bandwidth.
OC-12
A fiber optic line carrying 622.08 Mbps of bandwidth.
Optical Carrier-3
See OC-3.
Optical Carrier-12
See OC-12.
VoIP Glossary 17
VoIP Glossary—Terms and Definitions
PABX
See PBX.
Packet
A logically grouped unit of data. Packets contain a
payload (the information to be transmitted), originator,
destination, and synchronization information.
The idea with packets is to transmit them over a network
so each individual packet can be sent along the
most optimal route to its destination. Packets are constructed
on one end of the communication and deconstructed
on the receiving end based on the header
addressing information at the front of each packet.
Routers in the network will store and forward packets
based on network delays, errors, and re-transmittal
requests from the receiving end.
Packet switching
A means of economically sending and receiving data
over multiple network channels. Packet switching
takes data and breaks it down into packets—small
bundles of information containing the payload and
routing information. The packets are then transmitted
to the receiving end, where they are converted
back to the original data format. One feature of
packet switching is that packets can be received out of
order and then be quickly arranged into the correct
order. There are slow packet switching networks—like
the old SNA networks—and fast packet networks
based on Frame Relay and ATM. Although traditionally
used for data, packet networks—especially wellmanaged
ones—are suitable for real-time transmission
of voice and video.
Packet transfer mode
See PTM on page 18.
PBX
In telephony, a private branch exchange (PBX) (also
called a private automatic branch exchange or PABX)
system behaves as a customer’s premises over trunk
lines (thus the term branch). At first, PBXs mimicked
a small telephone company switchboard. Users would
use an operator to make telephone calls to the PSTN
(public switched telephone network). Now, users dial
directly, without using an operator; computer telephony
platforms such as automated attendants are
able to route incoming calls automatically, too.
Plain old telephone system
See POTS.
Point of presence
See PoP.
Point-to-point protocol
See PPP.
Point-to-point protocol over Ethernet
See PPPoE.
PoP
An acronym for point of presence. The Network Service
Provider’s access point on a Network Access Provider’s
network.
POP
Short for post office protocol, an Internet standard for
storage and retrieval of email messages.
Post office protocol
See POP.
Post, telegraph, and telephone
See PTT.
POTS
An acronym for Plain Old Telephone Service. Standard
telephone service over the PSTN, with an analog
bandwidth of less than 4 kHz. See also PSTN.
POTS splitter
A device that filters out the DSL signal and allows
POTS frequencies to pass through.
PPP
An acronym for Point-to-Point Protocol. A protocol for
packet transmission over serial links, specified by RFC
1661.
VoIP Glossary 18
VoIP Glossary—Terms and Definitions
PPPoE
An acronym for Point-to-Point Protocol over Ethernet.
A method for establishing sessions and encapsulating
PPP packets over an Ethernet, specified by RFC
2516.
Private automatic branch exchange
See PBX on page 17.
Private branch exchange
See PBX on page 17.
Protocol
A set of rules that determines the behavior of devices
in achieving and maintaining communication.
PSTN
An acronym for Public Switched Telephone Network. A
network shared among many users who can use telephones
to establish connections between two points.
Also known as dial network.
PSTN backup
See PSTN failover.
PSTN failover
PSTN failover lines are used as backup connections in
case your Internet connection is not available. These
are optional ports on ATA devices or IP phones that
connect directly to the analog PSTN lines coming
from the telco. This setup requires having both a regular
analog telephone lines and an account with a
VoIP Service Provider.

PSTN (POTS) gateway
Software that enables H.323 clients to make outgoing
calls, and for incoming calls to be routed to
H.323 clients.
PTM
An acronym for Packet Transfer Mode. PTM is a type
of data communication that is not synchronized by a
clock. Data is broken into variable-size units of data,
and those packets are relayed from one node to
another, often in multiple parallel paths, until they
reach their final destination. PTM framing caries
between 2-9% overhead depending on packet size.
PTT
An acronym for Post, Telegraph, and Telephone. A
national communications authority, sometimes government-
controlled and monopolistic, which acts as a
common carrier.
Public switched telephone network
See PSTN.
Punchdown block
An array of connectors used for connecting cable circuits
of a network interface.
QoS
Measure of how well a transmission system performs
in terms of transmission quality and service availability.
As a concept, QoS means that transmission rates,
error rates, and other characteristics can be measured,
improved, and, within limits, guaranteed in advance.
QoS incorporates bandwidth, latency, and jitter to
describe a network’s ability to customize the treatment
of specific classes of data. For example, QoS can be
used to prioritize audio transmissions over Web
browsing traffic.
Quality of service
See QoS.
RBOC
Short for Regional Bell Operating Company, the seven
companies formed to manage the local exchanges
originally owned by AT&T.
Real-time
Communications wherein perceptible delays between
the sender and receiver are minimal and easily tolerated
are considered to take place in real-time. Regular
telephone calls are real time. Point-to-point fax transmissions
are near to real-time. Voice messaging is not
real-time.
Regional Bell operating company
See RBOC.
VoIP Glossary 19
VoIP Glossary—Terms and Definitions
Registered jack-11
See Registered jack-11.
Registered jack-45
See RJ-45.
RJ-11
The designation for connecting a tip and ring circuit
to a standard, modular, 6-position jack.
RJ-45
Eight-position modular connector used for data transmission
over standard twisted or flat pairs.
Router
A device that connects LANs by dynamically routing
data according to destination and available routes.
RSVP
Short for resource reservation protocol, RSVP is a protocol
used in VoIP to manage QoS. Defined in RFC
2205: Resource ReSerVation Protocol (RSVP), RSVP
works by requesting that required bandwidth and
latency be “reserved” for the VoIP telephone call by
every network device between the two endpoints.
RTP
Acronym for real-time transport protocol, RTP encapsulates
VoIP data packets inside UDP packets.
Defined in RFC 3550—RTP: A Transport Protocol for
Real-Time Applications, RTP provides end-to-end network
transport functions suitable for applications
transmitting real-time data, such as audio, video or
simulation data, over multicast or unicast network
services. RTP does not address resource reservation
and does not guarantee quality-of-service for real-time
services. The data transport is augmented by a control
protocol (RTCP) to allow monitoring of the data
delivery in a manner scalable to large multicast networks,
and to provide minimal control and identification
functionality.
SDH
An acronym for synchronous digital hierarchy. This is
the European standard for metropolitan fiber rings,
used by ILECs. SDH handles multiple data types
(voice, video, and so on). The minimum rate for
SDH is 155 Mbps, the maximum is 2.488 Gbps.
Service level agreement
See SLA on page 20.
Service provider
A company that provides services to Internet, telephone,
and mobile phone users.
Session initiation protocol
See SIP on page 20.
SFP
An acronym for Small Form-factor Pluggable. A specification
for modular optical transceivers.
Sidetone
Sidetone is a technique in which the speaker’s voice is
played through the telephone earpiece locally so that
the speaker, subconsciously hearing his or her voice
instead of silence, will use the telephone
more comfortably.
Signaling system #7 (SSY7)
The basis for routing traffic with out-of-band signaling.

Its forerunner, CCIS (Common Channel Interoffice
Signaling), used 4.8 kbps data links to transmit
call set up and tear down messages to switching office
adjunct computers and packet switches. SS7 in itself is
not a network service offering, but rather the underlying
infrastructure upon which many existing and proposed
offerings are based. For example, local Basic
Rate ISDN (BRI) services can tap into SS7, so 64
kbps packetized data can be routed with the help of
the network’s out-of-band signaling capability. In
addition, nationwide Primary Rate ISDN (PRI) services
can use the same backbone.
Silence suppression
70–80% of a phone conversation consists of silence,
the rest being used for talking. To save bandwidth,
silence activity detection (SAD) and voice activity
detection (VAD) techniques are used to avoid transmitting
the silent portions of the conversation,
thereby saving up to 35% of the bandwidth. A packet
VoIP Glossary 20
VoIP Glossary—Terms and Definitions
is sent called a silence indicator (SID) to notify the
other end that the voice activity power level has
dropped below a certain threshold (-50 dbm, for
example) thereby marking a silent period. VAD
requires a 5-ms look-ahead buffer so this adds delay to
the voice path, so VAD is generally used only on
WAN circuits. One problem with SAD/VAD is that
the natural silences that occur between talking actually
contains sounds such as breathing and other background
noises that users are not consciously aware of.
Therefore, when VAD replaces these subliminal noises
with pure silence, it is off-putting to the users; so techniques
are employed to add white (or pink) random
noise (called comfort noise) locally to simulate this
background noise.
SIP
Short for session initiation protocol, SIP is an Internet
Engineering Task Force (IETF) standard protocol for
initiating an interactive user session that involves multimedia
elements such as video, voice, chat, gaming,
and virtual reality. Like HTTP or SMTP, SIP works in
the Application layer of the ̣Open Systems Interconnection
(OSI) communications model. The Application
layer is the level responsible for ensuring that
communication is possible. SIP can establish multimedia
sessions or Internet telephony calls and modify
or terminate them.
SLA
An acronym for Service Level Agreement. The contract
between the subscriber or operator and service provider
specifying the agreed to service level commitments
and related business agreement.
Softphone
A softphone is a software application that loads the
VoIP service onto your desktop computer or laptop.
Softphone applications enable you to place VoIP calls
from your computer to any location if you have access
to a broadband connection.
Softswitch
Short for software switch (also referred to as a media
gateway controller, gatekeeper, and call agent), a softswitch
is a software-based switching platform that links
IP networks to the PSTN and manages traffic containing
a mix of voice, fax, data, and video.
SOHO or SoHo
Acronym for small office, home office, a term that refers
to people who work in very small businesses or
home offices.
SONET
An acronym for synchronous optical network. This is
the ANSI standard for metropolitan fiber rings, used
by ILECs. Traffic is carried in an electronic packet
transported over fiber, using dual counter-rotating
rings. The SONET standard defines a hierarchy of
interface rates that allow data streams at different rates
to be multiplexed. It establishes Optical Carrier (OC)
levels from 51.8 Mbps to 2.48 Gbps (10 Gbps
for OC-192).
Speech recognition
Speech recognition describes a technology that enable
callers to speak words that are used to
control applications.
Store and forward
The method for storing a message or transmission for
later playback or transmission. As opposed to realtime
communication, store and forward is the basis
for all messaging systems, including email, fax-ondemand,
unified messaging, etc. In data communications,
store and forward applies to momentary buffering
of packets or other data strings.
T1

A digital transmission with a capacity of 1.544 Mbps
used in North America. A T1 may be channelized
into 24 DS0s, each capable of carrying a single voice
conversation or data stream. T1 may be carried on
coaxial cable or two twisted pairs.
T3
North American standard for DS-3. Operates at a signaling
rate of 44.736 Mbps, or the equivalent of
28 T1s.
VoIP Glossary 21
VoIP Glossary—Terms and Definitions
TC-PAM
An acronym for Trellis-Coded Pulse-Amplitude Modulation,
Modulation format that is used in HDSL2 and
G.SHDSL. It is a variant of trellis coded modulation
(TCM) which uses a one-dimensional pulse-amplitude
modulation (PAM) symbol space, as opposed to
a two-dimensional quadrature amplitude modulation
(QAM) symbol space. TC-PAM is spectrally compatible
with all other forms of DSL.
TCP
An acronym for transmission control protocol, The
transport layer protocol developed for the ARPAnet
which comprises layers 4 and 5 of the OSI model.
TCP controls sequential data exchange in TCP/IP for
remotely hosts in a peer-to-peer network. See also IP
on page 14.
Telco
Telephone company.
Telephony
Taken from Greek root words meaning far sound,
telephony means the process of converting or transmitting
voice or other signals over a distance, and
then re-converting them to an audible sound at the far
end.
Touch tone
See DTMF on page 10.
TR-069
Technical Report 069, is a specification for remote
management of end user devices (CPEs).
Traffic shaping
Traffic shaping (also known as metering, shaping, and
smoothing) refers to the use of queues to reduce surges
that can clog a network. Data is buffered in a queue
and then released to the network in set amounts to
ensure that the traffic will fit within the promised traffic
limits for the particular connection. Traffic shaping
is used in ATM, Frame Relay, and other types
of networks.
Transmission control protocol
See TCP.
μ-law or u-law
μ-law or u-law is an audio codec companding format
in which the signal is compressed on input and
expanded back to its original form on output. More
correctly known as mu-law, it performs logarithmic
mapping between an 8-bit data space and 14-bit sample
space as described in the CCITT G.711 recommendation.
þμ-law has 14 bits of dynamic range (84
dB).þSee also A-law on page 6 and G.711 on page 11.
UNIX
A multi-user, multi-tasking operating system originally
developed in 1969 by Ken Thompson of AT&T
Bell Laboratories. UNIX is used in telephone company
and mission-critical applications.
Upstream
In the direction of the telephone network or server.
UTP
An acronym for Unshielded Twisted Pair.
VAD
See Silence suppression on page 19.
VDSL2
An acronym for Very High Bit Rate Digital Subscriber
Line 2. Similar to ADSL, VDSL2 is a type of DSL utilizing
DMT. At longer distances the transmission provides
a higher downstream (to the customer site) than
upstream (to the service provider). On short loops
VDSL2 can offer symmetrical performance. A single
twisted pair offers up to 200 Mbps downstream. A
new 35b profile allows for up to 400 Mbps downstream.
Vectoring
Also known as G.vector or VDSL2 vectoring. Vectoring
is a transmission method that employs the coordination
of line signals for the reduction of self-FEXT
(far-end crosstalk) levels in both the downstream and
upstream directions.
VoIP Glossary 22
VoIP Glossary—Terms and Definitions
Very high bit rate digital subscriber line 2
See VDSL2 on page 21.
VioIP
Short for video over IP (also called IP streaming video),
VioIP enables video signals to be transported and
managed over IP networks. With VioIP, live or prerecorded
video content is captured and compressed,
then transmitted via the network to one or more
receiving stations for viewing.
Video-over-IP
See VioIP.
Voice activity detection
See Silence suppression on page 19.
Voice quality
Human speech uses a bandwidth of 100 Hz to 10
kHz (if you include harmonics) with most of the
speech occurring in the 100 Hz to 3 kHz range. The
more bandwidth that is allocated to reproduce speech,
the more faithfully the sound compares to the original,

 

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