Administrator's Guide

Issue 5 October 2002 1991555-233-506

Personal terminal

PTC

Positive temperature coefficient

PTT

Postal Telephone and Telegraph

public network

The network that can be openly accessed by all customers for local and long-distance calling.

pulse-code modulation (PCM)

An extension of pulse-amplitude modulation (PAM) in which carrier-signal pulses modulated by an analog

signal, such as speech, are quantized and encoded to a digital, usually binary, format.

QoS

Quality of Service

QPPCN

Quality Protection Plan Change Notice

quadrant

A group of six contiguous DS0s in fixed locations on an ISDN-PRI facility. Note that this term comes from

T1 terminology (one-fourth of a T1), but there are five quadrants on an E1 ISDN-PRI facility (30B + D).

queue

An ordered sequence of calls waiting to be processed.

queuing

The process of holding calls in order of their arrival to await connection to an attendant, to an answering

group, or to an idle trunk. Calls are automatically connected in first-in, first-out sequence.

RAM

See random-access memory (RAM).

random-access memory (RAM)

A storage arrangement whereby information can be retrieved at a speed independent of the location of the

stored information.

RBS

Robbed-bit signaling

RBVD

Robbed-bit AVD

Radio controller