PABX

Private Automated Branch Exchange
 - Allows central control of incoming call via a single operator.

Packet Switching

The method used to move data and voice around a network. In packet switching, all the data is broken up into chunks - each chunk has the address of where it came from and where it is going. This enables chunks of data from many different sources to co-mingle on the same lines and be sorted and directed along different routes by special machines along the way. In this way many people can use the same lines at the same time.

PAN

Personal Area Network
 - Standards being developed by IEEE 802.15 based on radio (Bluetooth) technology.

Parallel Port

Port in a PC used for the connection of external equipment such as a printer, scanner etc.

Patch Port

Cabling connection point. This is typically the part of a structured network cabling system (cat 5) that enables switching of services either voice or data to RJ45 sockets.

PBX

Private Branch Exchange - 
(Also called PBX, Private Business eXchange or PABX for Private Automatic Branch eXchange) - a telephone exchange that is owned by a private business, as opposed to one owned by a common carrier or by a telephone company.

PCMCIA

Personal Computer Memory Card Industry Association

PCN

Personal Communications Network
 - A wireless phone service similar to cellular telephone service but emphasizing personal service and extended mobility.

PDA

Personal Digital Assistant
 - A term for any small mobile hand-held device that provides computing and information storage and retrieval capabilities for personal or business use.

PDF

Portable Document Format - A file format that has captured all the elements of a printed document as an electronic image that you can view, navigate, print, or forward to someone else.

Piconet

A single Bluetooth wireless personal area network containing up to 8 active devices.

Point of Presence

A Point of Presence usually means a city or location where a network can be connected to, often with dial up phone lines.

Portal

Usually used as a marketing term to describe a web site that is or is intended to be the first place people see when they are using the Web. Typically, a Portal site has a catalogue of web sites, a search engine or both. A Portal site may also offer Email and other services to entice people to use that site as their main "point of entry" to the web.

POT(S)

Plain Old Telephone (Service)

Power over Ethernet

The provision of up to 12 watts of dc power over Ethernet twisted-pair cabling, specified by IEEE 802.3af. Also know as PoE.

PPP

Point to Point Protocol
 - Successor to SLIP Provides router-to-router and host-to-network connections over both synchronous and synchronous circuits.

Predictive Dialling

A third party CTI application, predictive dialling removes all dialling responsibilities from an agent. Once a call has been completed the software automatically dials the next number on the agent's call list.

PRI

Primary Rate ISDN - 
(ISDN30e) provides up to 30 "B" channels, giving users 30 lines that can be used for any combination of voice, data and video.

Primary Rate

An ISDN circuit providing (in Europe) up to 30 x 64 kbit/sec bearer channels for use by data or speech and two 16 kbit/sec control channels. Up to 30 independent calls can be carried at the same time on one Primary Rate.

Private circuit

Point to Point private communications link. (Not switched).

Protocol

A set of rules and conventions by which two computers pass messages across a network. Two devices require a common protocol in order to communicate.

PSDN

Packet Switched Data Network

PSTN

Public Switched Telephone Network
 - Exchange lines provided by a network provider.

Public Network Interface

A point of demarcation between public and private network. In many cases the public network interface is the point of connection between the network provider's facilities and the customer premises cabling.

Pulse Dialling

Also known as LD (loop-disconnect) dialling. A method of dialling where the telephone is alternately disconnected and connected to signal to the exchange. For example if a digit 5 is dialled this could be signalled by sending 5 disconnection pulses. The frequency and length of the pulses and the number of pulses for each digit can vary from country to country. This dialling method is now mostly superseded by tone dialling.