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PACS

Personal Access Communication System; a digital cordless technology developed initially by Bell Labs in the US, PACS was designed to compete with DECT

Packet switching

A communication system wherein the information is transmitted in packets of a set size. These packets have address headers and find their way to their destination by the most efficient route through the network. Compared to circuit switching where a connection is occupied until the traffic exchange is completed, packet switching offers considerable efficiencies as connections can be used by a number of users simultaneously

PAMR

Public Access Mobile Radio; Commercial service using trunking techniques in which multiple groups of users can set up their own closed systems within a shared public network

PAP

Public Access Profile; a DECT term

PCH

Paging Channel; downlink only, the MS is informed of incoming calls by the BTS via the PCH

PCM

Pulse Code Modulation; the standard digital voice format at 64kbit/s

PCMCIA

Personal Computer Memory Card Interface Association the body responsible for defining the standards and formats for memory expansion cards for laptop computers and PDAs. Now extended to cover cards for mobile phones

PCN

Personal Communications Network; a designation initially used in the UK to refer to networks operating in the 1800MHz band (see also DCS1800). No longer in use

PCS 1900

Personal Communications Systems 1900MHz; the terminology used in the US to describe the new digital networks being deployed in the 1900MHz band; rarely used today

PCU

Packet Control Unit; an element in a GPRS/UMTS network

PDA

Personal Digital Assistant

PDC

Personal Digital Communications; a digital cellular technology developed and deployed uniquely in Japan. A TDMA technology, PDC is incompatible with any other digital cellular standard

PEDC

Pan European Digital Communications; A designation occasionally used in the early 1990’s to describe GSM. No longer in use

Penetration

The percentage of the total population which owns a mobile phone

PHS / PHP

Personal HandyPhone System/Phone; a digital cordless technology developed in Japan which achieved great success. Deployed by NTT DoCoMo and other Japanese operators PHS offered two-way communications, data services and Internet access and eventually won some 28 million customers. Now in decline as cellular’s wide area capabilities offer better service

Personal Identifier Number

PKI

Public Key Infrastructure

PLMN

Public Land Mobile Network; any cellular operator’s network

PMR

Private Mobile Radiocommunications; two-way radio technology widely used for despatch and delivery services, taxi companies and the like. See TETRA

POCSAG

Post Office Code Standardisation Group; a now defunct industry grouping which standardised pager addressing systems

PoP

Points of Presence; a method of measuring the value of a cellular licence; the approximate number of potential customers within a geographical area

POTS

Plain Old Telephone Service

PROM

Programmable Read Only Memory

PSK

Phase Shift Keying

PSRCP

Public Safety Radio Communications Project; an initiative by the UK Government to standardise all emergency services communications on to a single digital technology (see TETRA)

PSDN

Public Switched Data Network

PSPDN

Public Switched Packet Data Network

PSTN

Public Switched Telephone Network

PSU

Power Supply Unit

PTO

Public Telecommunication Operator

PTT

Posts, Telephone and Telegraph Administration

PTT

Push-to-Talk; a feature of PMR systems

PWT

Personal Wireless Telecommunications; a variant of DECT developed for use in the USA

The Consumer Mobile Glossary

PCN

Personal Communications Networks; an outdated term for GSM services in the 1800MHz band

PDA

Personal Digital Assistant; a sophisticated handheld device with advanced display facilities and a range of business-oriented software programs

Phone book

A list of personal names and numbers stored in a mobile phone’s internal memory or in the SIM card. These numbers can be called by accessing the appropriate memory and making a single key stroke

Personal Identity Number; a number, usually four digits, that must be keyed into a mobile phone to make it work. A security measure to prevent unauthorised usage

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