DEFINITY Enterprise Communications Server Release 8.2
Upgrades and Additions for R8r
555-233-115 Issue 1
April 2000
Glossary and Abbreviations

GL-41

protocol
A set of conventions or rules governing the format and timing of message exchanges to control
data movement and correction of errors.
PSC
Premises service consultant
PSDN
Packet-switch public data network
PT 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-d istance 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 encod ed to a digital, usually binary, format.
Q
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.
R
RAM
See random-ac cess memory (RAM).
random-access memory (RAM)
A storage arrangement whereby information can be retrieved at a speed independ ent of the
location of the stored information.