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Glossary and Abbreviations
Issue 5 January 1998 GL-39555-230-024
PL
Private line
PLS
Premises Lightwave System
PMS
Property Management System
PN
Port network
PNA
Private network access
POE
Processor occupancy evaluation
POP
Point of presence
port
A data- or voice-transmission access point on a device that is used for communicating with other
devices.
port carrier
A carrier in a multicarrier cabinet or a single-carrier cabinet containing port circuit packs, power
units, and service circuits. Also called a port cabinet in a single-carrier cabinet.
port network (PN)
A cabinet containing a TDM bus and packet bus to which the following components are
connected: port circuit packs, one or two tone-clock circuit packs, a maintenance circuit pack,
service circuit packs, and (optionally) up to four expansion interface (EI) circuit packs in
DEFINITY ECS. Each PN is controlled either locally or remotely by a switch processing element
(SPE). See also expansion port network (EPN) and processor port network (PPN).
port-network connectivity
The interconnection of port networks (PNs), regardless of whether the configuration uses direct or
switched connectivity.
PPM
1. Parts per million
2. Periodic pulse metering
PPN
See processor port network (PPN).
PRI
See Primary Rate Interface (PRI).
primary extension
The main extension associated with the physical voice or data terminal.
Primary Rate Interface (PRI)
A standard ISDN frame format that specifies the protocol used between two or more
communications systems. PRI runs at 1.544 Mbps and, as used in North America, provides 23
64-kbps B-channels (voice or data) and one 64-kbps D-channel (signaling). The D-channel is the
24th channel of the interface and contains multiplexed signaling information for the other 23
channels.