Switching to VoIP

This is the Title of the Book, eMatter Edition

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445

Glossary

adaptive differential pulse code modulation (ADPCM)

An advanced, compressed version of plain

PCM digitizing. This algorithm is used by

the G.726 codec.

additive noise

any unwanted signal that distorts a phone

call by increasing the strength of the

sound signal.

Alaw

The scale used by PCM digitizing algo-

rithms in many countries outside North

America.

asynchronous transfer mode (ATM)

A buffered switching system that trans-

ports packets called cells across

packet-based, often optical, data links.

autoattendant

A telephony application that provides

interactive prompts and greetings for

incoming calls to a PBX, so that calls can

be routed without intervention from a

human reception operator.

automated location identifier (ALI)

The signaling using to notify emergency

dispatchers of a caller’s postal address on

the 911 system.

automatic call distribution (ACD)

Also called automatic call delivery, a tele-

phony application that routes inbound

calls to the appropriate answering party

based on a logic-based algorithm, such as

the originating area code or the language

the caller speaks—i.e., Spanish or English,

etc.

baby bells

Nickname for incumbent local exchange

carriers (ILECs), the companies that

sprung from the AT&T antitrust breakup

of the early 1980s.

basic rate interface (BRI)

An ITU signaling