P: P Connector-Pyramidal Horn

P Connector-pALI

P Connector

Also called a male amp connector or 25-pair male connector. The female version is called a C connector.


pseudo-ANI. A cellular term . p-ANI is a fictitious non-dialable telephone number which comprises the seven to ten digits of the cell site or base station identifier. p-ANI information is used by the PSAP (Public Safety Answering Position) in a wireless E-911 (Enhanced-911) application in order that the 911 personnel can locate the caller. Along with p-ANI information are sent the 10 digits of the cellular calling number, also known as the MDN (Mobile Dialing Number), in order that the 911 personnel can callback for more information. The FCC has mandated that, in the future, p-ANI information will be used to identify the specific location of the caller, within a range of 125 meters . See also E-911 Service and PSAP.


The Precise or Protected Code. A very long sequence of pseudo random binary biphase modulations on the GPS (Global Positioning System) carrier at a chip rate of 10.23 MHz which repeats every 267 days. Each one week segment of this code is unique to one GPS satellite and is reset each week.


Predictive framing, specified by the MPEG Recommendation. Pictures are coded through a process of predicting the current frame using a past frame. The picture is broken up into 16x16 pixel blocks and each block is compared to a previous frame's block that occupies the same vertical and horizontal position.


Packet Media Access Control. An FDDI-II term. See FDDI-II.


Enhanced Business Service (also known as P-Phone) is an analog Centrex offering provided by Northern Telecom. It operates over a single-pair subscriber loop., providing normal full duplex audio conversations and a secondary 8 KHz half-duplex amplitude shift-keyed signal, which is used to transmit signaling information to and from the Northern Telecom-equipped central office.

P-type Semiconductor

See Semiconductor.


Peak to Average Ratio. A standard analog transmission-line test signal of varying frequencies and amplitudes, which is then compared with the received signal. Composite results are a weighted number from 1 to 100 being the maximum. The P/AR is used increasingly as a standard quick test of a telecommunications channel comparative quality. Per Bell standard, the minimal acceptable P/AR rating for medium-speed data transmission is 48.

P/E Ratio

See Price Earnings Ratio.

P.139 Serial Bus

The P.139 Serial Bus is promulgated by the IEEE (202-371- 0101). Initially it will operate at 100 million bits per second. But it has extensions for 200 and 400 megabits per second. The cable topology allows for branching and daisychaining of the peripherals attache, with a maximum of 32 4.5 meter hops using the baseline copper cable. That cable is a specially-designed combination consisting of two shielded twisted pairs for clock and data, two wires for power and ground and an overall shield that surrounds the twisted pairs and power and ground wires. See also USB, which stands for Universal Serial Bus.


The ITU-T specification "Methods for Subjective Determination of Voice Quality."

P.800 involves the subjective evaluation of preselected voice samples of voice encoding and compression algorithms by a panel of "expert listeners" comprising a mixed group of men and women under controlled conditions. The result of the evaluation is a Mean Opinion Score (MOS) in a range from 1 to 5, with 1 being "bad" and 5 being " excellent ." Pulse Code Modulation (PCM), the encoding standard traditionally used in most circuit-switched PSTN (Public Switched Telephone Network) environments, rates a MOS of 4.4, with 4.0 considered to be "toll quality." See also MOS, P.861, and Toll Quality.


The ITU-T specification "Objective Quality Measurement of Telephone Band (300- 3400 Hz) Speech Codecs," P.861 builds on the subjective P.800. P.861 is an intrusive automated method which rates voice quality based on comparison of a predefined speech sample before and after transmission through a codec and/or network. P.861 describes Perceptual Speech Quality Measure (PSQM) as the automated rating method. The PSQM algorithm attempts to measure distortion in an "internal psychoacoustic domain," which mimics the sound perception of humans in real-life situations. The PSQM conversion of signals in the physical domain (e.g., frequency and time) to the more meaningful psychoacoustic domain, the process provides a quantifiable, objective rating, rather than the subjective rating offered by the P.800 specification. The source signal is specified in ITU-T P.50 as an artificial voice with an active speech level of -20dBm, which includes both male and female genders, and which reproduces many the essential characteristics of human speech. The output of the test process is a PSQM value ranging from 0 to 6.5, with 0 being perfect quality and 6.5 being the highest level of signal degradation. Note that the PSQM value of PCM (Pulse Code Modulation), the traditional method for converting voice signals from analog to digital format in PSTN applications, is 0.5. This value reflects a relatively minor difference between the analog input and the uncompressed digital output of the encoding process. See also MOS, P.800, and Toll Quality.

P0 Protocol

The protocol for messaging headers used for undefined messaging in an X.400 MHS (Message Handling System). Not officially part of the X.400 standards but became the U.S. intercept solution to P35 and X.435. See POP and POP3.

P01, P.01, Pnn or P.nn

The Grade of Service for a telephone system. The digits following the P, i.e. nn, indicate the number of calls per hundred that are or can be blocked by the system. It is a goal or a measure of an event. In this example, P01 (also spelled P.01) means one call in a hundred (i.e. one divided by 100) can be blocked, so the system is designed to meet this criterion. See Grade of Service and Traffic Engineering.

P1 Protocol

P1 is the protocol defined in the X.400 standard used between MTAs (Message Transfer Agents) for relaying messages. Defined as the envelope, P1 is a portion of an X.400 message the identifies the message originator and potential recipients, records information about the message's path through the MTS (Message Transfer Service), directs the message's subsequent movement through the MTS, and includes characteristics of the message's contents. The composition of an envelope changes as the message is submitted, relayed and delivered.

P2 Format

The 1984 defined message format, or protocol, used between cooperating User Agents in the IPM (Interpersonal Messaging System). The P2 heading is a component of an IP-message that indicates such items as the originator, recipients(s) and subject of the message.


  1. Peer-to-Peer. Think of Napster or Gnutella, the music people. You sign up. Your computer and its hard disk become part of a giant network. Now you can go to anyone else's hard disk and download the music you wish. Downloading music hogged the P2P headlines, but the ideas behind the P2P networking stirred lots of imaginations. Some argued that the technology had been around for a long time ” the video chat and NetMeeting-style software from Intel, Microsoft, CU-See Me, and others are P2P ” but the generalized idea of a dispersed, searchable, serverless database of files is the real story behind P2P. Napster does, of course, have a central database, but it gets out of the way once you've found what you're looking for, and lets the PCs with the music commune among themselves . Can you use technology like this, asked PC Magazine, for non-musical purposes? Sure, and it tested several new collaboration tools using P2P. which it liked . Said the magazine, "Individuals become a part of an open collaboration community, thereby overcoming the barriers of traditional closed collaboration systems." P2P is also being used to make voice calls over the Internet. See Skype.

  2. Person To Person. Another web term that says one person sells something to another person. It's commonly used in the auction business. One person selling something like a used camera to another person.

P3 Protocol

X.400 standard protocol used between a RUA (Remote User Agent) and an MTA (Message Transfer Agent) and an MTA (Message Transfer Agent) or between a remote MS (Message Store) and an MTA. P3 may be used optically between a co-resident UA (User Agent) and MTA. See P3P


Platform for Privacy Preferences Project. P3P is a way of that Web sites you visit could capture a great deal of information about you ” so long as you allow that capture. You have control over how much information also. Writing about P3P, the New York Times' John Markoff said, "the new standard establishes a complicated computerized negotiation that dramatically extends both the information-gathering potential and the privacy-protection possibilities inherent in each visit to a Web site." The P3P standard, wrote Markoff, "foreshadows new Internet technology that will make each visit to a Web site a complicated exchange of information in which a personal computer will have the opportunity to automatically disclose a range of information covering every conceivable category, from birth data to shoe size , depending on rules set by the computer user. At the same time, the Web site will be forced to disclose its policy for using the information it is gathering. hopefully giving the computer user the ability to decline to share data about himself."

P5 Protocol

The 1984 X.400 protocol used between a MTA (Message Transfer Agent) and a Teletex Unit. This protocol is not popular.


Intel's successor to the Pentium processor. The P6 is now called the Pentium Pro.

P7 Protocol

The protocol used between a UA (User Agent) and a MS (Message Store). Defined in the 1988 X.400 standard.

P22 Format

An enchanted version of the P2 format that appeared in the 1988 X.400 standard.


Pulse to Tone & Rotary Dial Recognition products.

P35 Format

The EDI (Electronic Data Interchange) message header enhancement to X.400 that enables EDI-specific addressing, routing and handling of EDI messaging. Defined in 1990 in the X.435 standard.


P802.11 is a series of evolving standards in the wireless Local Area Network arena. The IEEE Program P802.11 Standards Working Group aims to define universal protocols for wireless LANs in the 900 MHz, 2.4 GHz and infrared frequency bands. Main components in the 802.11 standard are twofold:

  1. The physical specifications for medium- dependent protocols. There are different physical specifications for each frequency band supported in 802.11.

  2. The Medium Access Control (MAC) specifications for ad-hoc wireless networks and wireless network infrastructures . A single medium-independent MAC protocol provides a unified network interface between different wireless PHYs (Physical Specifications) and wired networks. See 802.11.


  1. Public Address. Loud speaker system, sometimes used for paging.

  2. Pooling Administrator. See Number Pooling.


Private Automatic Branch eXchange. Originally, PBX was the word for a switch inside a private business (as against one serving the public). PBX means a Private Branch Exchange. Such a "PBX" was typically a manual device, requiring operator assistance to complete a call. Then the PBX went "modern" (i.e. automatic) and no operator was needed any longer to complete outgoing calls. You could dial "9." Thus it became a "PABX." Now all PABXs are modern. And a PABX is now commonly referred to as a "PBX.


Personal Activity Center. A combination IBM PC clone, alarm clock, answering machine, speakerphone, fax machine, modem, compact-disk player and AM/FM radio all rolled into one unit sitting on your desk.

Pac Bell

Pacific Bell, the California Bell Operating Company (BOC) which, along with Nevada Bell, formed Pacific Telesis (PacTel). PacTel was one of the seven original Regional Bell Operating Companies (RBOCs) formed in 1984 by the Modified Final Judgement (MFJ). As PacTel was acquired by SBC Corporation (Southwestern Bell) in 1996, Pac Bell is now a subsidiary of SBC.

Pacific Telesis

One of the seven, independent Regional Holding Companies (RHCs) formed by the Divestiture of AT&T of 1984. Pacific Telesis held Pacific Bell, Nevada Bell and several non- regulated subsidiaries. In 1996, SBC Corporation bought Pacific Telesis. Pacific Telesis no longer exists. Pacific Bell and Nevada Bell retained their identities. See also RBOC.


Controlled rate of flow dictated by the receiving component, to prevent congestion. A method of flow control in IBM's SNA. See Pacing Group.

Pacing Algorithm

The mathematical rules established to control the rate at which calls are placed by an automatic dialing machine, also called a predictive dialer. See Predictive Dialer.

Pacing Control

SNA term for flow control. See Pacing Group.

Pacing Group

In IBM's SNA, the number of data units (Path Information Units, or PIUs) that can be sent before a response is received. An IBM term for window.


To compress data items so they take up less space. A process used by many database programs to remove records marked for deletion.


  1. Generic term for a bundle of data, usually in binary form, organized in a specific way for transmission. The specific native protocol of the data network may term the packet as a packet, block, frame or cell. A packet consists of the data to be transmitted and certain control information. The three principal elements of a packet include:

  2. Header ” control information such as synchronizing bits, address of the destination or target device, address of originating device, length of packet, etc.

  3. Text or payload ” the data to be transmitted. The payload may be fixed in length (e.g., X.25 packets and ATM cells ), or variable in length (e.g., Ethernet and Frame Relay frames ).

  4. Trailer ” end of packet, and error detection and correction bits. See also Block, Cell and Frame.

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  5. Specific packaging of data in a packet-switched network, such as X.25, Frame Relay or ATM. A true packet-switched network such as X.25 involves packets of a specific and fixed length. In a public packet switched network, such packet payloads originally were specified as being either 128B or 256B, where B=Byte. In later versions of the standards, that packet size was increased to a maximum of 4,096B, although the packet payload size generally does not exceed either 512B or 1024B. The larger packet size traditionally is used in airline reservation systems and other applications where relatively large sets of data routinely are transmitted. A X.25 packet prepends the payload with header information including a flag of eight bits; the flag denotes the beginning of the packet and also serves to assist the network nodes (packet switches) in synchronizing on the rate of transmission. An address field of eight bits also prepends the payload, with four bits identifying the target device and four bits identifying the transmitting device. Control data of eight-to- sixteen bits comprise the last element of the header; included in control data is the packet number in order that the network nodes might identify and correct for lost or errored packets. Appending the payload is a trailer consisting of a Cyclic Redundancy Check (CRC), which is used by all packet nodes for purposes of error detection and correction. See ATM, CRC, Frame Relay, Packet Assembler/Disassembler (PAD), X.25.

Packet Assembler/Disassembler

PAD. A hardware/software combination that forms the interface between a X.25 network such as PDN and an asynchronous device such as a PC. The PAD generates call request, call clear, and other information packets in addition to the ones that contain user data. The PAD is responsible for packetizing the data from the transmitting device before it is forwarded through the packet network. On the receiving end of the transmission, the PAD strips away the control information contained in the header and trailer in order to get at the original text or payload, in effect disassembling the packets and reconstituting the original set of data in its native or original form. The PAD may be in the form of a standalone DCE device on the customer premise and supporting one or more terminals, or in the form of a printed circuit board which fits into an expansion slot of the terminal. Smaller users generally rely on the carrier to provide the PAD, which is embedded in the packet switch.

Packet Buffer

Memory set aside for storing a packet awaiting transmission or for storing a received packet. The memory may be located in the network interface controller or in the computer to which the controller is connected. See Buffer.

Packet Burst Protocol

A protocol built on top of IPX that speeds the transfer of NCP data between a workstation and a NetWare server by eliminating the need to sequence and acknowledge each packet. With packet burst, the server sends a whole set (or burst) of packets before it requires an acknowledgement .

Packet Controller

The hub of the AT&T ISDN system. It acts as a fast packet switch providing virtual circuit services to the devices hooked to the system.

Packet Driver

The specification developed by John Romkey at FTP Software to allow TCP/IP and other transport protocols to share a common network interface card. Packet Drivers have been written for a variety of network interface cards, and in many cases provide NetWare compatibility.

Packet Filtering

Packet filtering is the recognition and selective transmission or blocking of individual packets based on destination addresses or other packet contents. Packet filtering can be an elementary form of firewall in that it can accept or reject packets based on predefined rules. This ability helps to control network traffic. See Packet Filtering Firewall.

Packet Filtering Firewall

A packet filtering firewall is a router or a computer running software that has been configured to block certain types of incoming and outgoing packets. A packet-filtering firewall screens packets based on information contained in the packets' TCP and IP headers, including some or all of the following: Source address; Destination address; Application or protocol; Source port number; and Destination port number. See Packet Filtering.

Packet Forwarding

Copying the packet to another node without looking at the destination address.

Packet Handler Function

The packet switching function within an ISDN switch, for the packet mode bearer service.

Packet Inspection

Essentially what it sounds like. Your device ” typically a switch ” looks at every packet it is moving around. Inspecting every packet that a switch switches gives the switch the ability to do neat things to the packets ” like rate limiting, quality of service (e.g. voice and video gets moved faster) and various levels of security (porn gets dropped, selective encryption, etc.)

Packet Interleaving

Refers to the process of multiplexing multiple incoming packets from multiple channels on to a single outgoing channel by sampling one or more packets from the first channel, then the next , and so on.

Packet Level

In packet data networking technology, level 3 of X.25. Defines how user messages are broken into packets, how calls are established and cleared over the packet data network (PDN) and how data flows across the entire PDN. The packet level also handles missing and duplicate packets.

Packet Level Procedure

PLP. A full-duplex protocol that defines the means of packet transfer between a X.25 DTE and a X.25 DCE. It supports packet sequencing, flow control (including maintenance of transmission speed), and error detection and recovery.

Packet Mode Bearer Service

An ISDN term for X.25 packet data transmission over the D channel in a BRI application. Always a part of the ITU-T (nee CCITT) standards, the 16-Kbps D channel can accomplish its primary responsibilities for signaling and control while still leaving 9.6 Kbps free for end user transmission of low-speed data. Retailers use of this service for credit card authorization. See also AO/DI, BRI and ISDN.

Packet over SONET

A metropolitan area network (MAN) or wide area network (WAN) transport technology that carries IP packets directly over SONET transmission without any data link facility such as ATM in between. Packet over SONET is intended to transmit data at the highest rates possible, because SONET has a smaller packet header overhead than ATM (28 bytes out of an 810-byte frame compared with 5 out of a 53-byte ATM cell).

Packet Overhead

A measure of the ratio of the total packet bits occupied by control information to the number of bits of data, usually expressed as a percent.

Packet Radio

Packet Radio is the transmission of data over radio using a version of the international standard X.25 data communications protocol adapted to radio (AX.25). It takes your information, and breaks it up into "packets" which are each sent and acknowledged separately. This assures error-free delivery from sender to receiver. A packet is a stream of characters consisting of a header, the information the user is sending, and a check sequence. The header gives the destination call sign, the call sign of the sender, and any digipeaters (digital repeater) call signs that will be used for relaying the packet. The check sequence makes certain that the data received is what was sent. AlohaNET, a packet radio network developed for a number of years ago for use at the University of Hawaii, was an early packet radio network for LAN networking among the islands and laying a foundation for subsequent packet networks, both wired and wireless. Packet radio data networks recently have been deployed by a number of carriers serving mobile and fleet applications, with such carriers including ARDIS, RAM Mobile Data and Nextel.

Packet Size

The length of a packet, expressed in bytes (B). Packet size is of specified and fixed length in X.25 and other true packet networks. The size of the "packet" in other networks may be variable within limits, as is the case with an Ethernet frame or a Frame Relay frame.

Packet Sniffer

Most data is now transmitted in packets. A packet sniffer is a piece of software that simply examines every packet on whichever circuit/s it's assigned to monitor. A packet sniffer could be used by a legitimate company to protect itself against unwanted intruders into its network. It could also be used by an intruder to monitor a data stream for a pattern such as a password or credit card numbers . See the Internet and IP.

Packet Switching

Sending data in packets through a network to some remote location. The data to be sent is assembled by the PAD (Packet Assembler/Disassembler) into individual packets of data, involving a process of segmentation or subdivision of larger sets of data as specified by the native protocol of the transmitting device. Each packet has a unique identification and each packet carries its own destination address. Thereby, each packet is independent, with multiple packets in a stream of packets often traversing the network from originating to destination packet switch by different routes. Since the packets may follow different physical paths of varying lengths, they may experience varying levels of propagation delay, also known as latency. Additionally, they may encounter varying levels of delay as they are held in packet buffers awaiting the availability of a subsequent circuit. Finally, they may be acted upon by varying numbers of packet switches in their journeys through the network, with each switch accomplishing the process of error detection and correction. As a result, the packets may also arrive in a different order than they were presented to the network. The packet sequence number allows the destination node to reassemble the packet data in the proper sequence before presenting it to the target device.

Originally developed to support interactive communications between asynchronous computers for time-share applications, packet switched networks are shared networks, based on the assumption of varying levels of latency and, thereby, yielding a high level of efficiency for digital data networking. Isochronous data such as realtime voice and video, on the other hand, are stream-oriented and highly intolerant of latency. As a result, packet switched networks are considered to be inappropriate for such applications. Recent development of certain software and making use of complex compression algorithms, however, has introduced packetized voice and video to the corporate intranets and the Internet, which was the first public packet-switched data network and remains by far the most heavily used.

Here is another way of explaining packet switching: There are two basic ways of making a call. First, the one everyone's familiar with ” the common phone call. You dial. Your local switch finds an unused path to the person you called and joins you. While you are speaking, the circuit is 100% all yours. It's dedicated to the conversation. This is called circuit switched. Packet switching is different. In packet switching, the "conversation" (which may be voice, video, images, data, etc.) is sliced into small packets of information. Each packet is given a unique identification and each packet carries its own destination address ” i.e. where it's going. Each packet may go by a different route. The packets may also arrive in a different order than how they were shipped. The identification and sequencing information on each packet lets the data be reassembled in proper sequence.

Packet switching is the way the Internet works. Circuit switching is the way the worldwide phone system works, also called the PSTN (Public Switched Telephone Network).

Packet and Circuit Switching each have their own significant advantages. Packet switching for example does a wonderful job getting oodles of data into circuits. Think about a voice conversation. When you are talking, he's listening. Therefore half the circuit is dead. There are pauses between your voice. Packet switching takes advantage of those pauses to send data. Packet switching has been used primarily for data. But with the growth of the Internet, it has been used also for voice. Because of the need to re-assemble packets and other reasons, there's up to a half second delay between talking and the person at the other end hearing anything. Packet voice on the Internet is not as clear as circuit switched voice. But that's changing as the packets come faster and the technology improves . See Internet, IP Telephony and TAPI 3.0.

Packet Switching Exchange

PSE. The part of a packet switching network that receives the data from a PAD Packet Assembly Disassembler) through a modem. The PSE makes and holds copies of each packet before sending them to the PSE they're addressed to. After the far-end PSE acknowledges receipt of the original, the copies are discarded.

Packet Switching Network

A network designed to carry data in the form of packets. See Packet Switching.

Packet Telephony

Another name for Internet Telephony. Also called Voice Over the Internet. See VoIP.

Packet Tracing

The monitoring and reporting a particular packet addresses or types for diagnostic purposes.

Packet Type Identifier

In packet data networking technology, the third octet in the packet header that identifies the packet's function and, if applicable , its sequence number.


A growing focus in the telecom industry away from voice-dominant (circuit-centric) networks and toward IP packet networks as the future delivery system for combined data and telephony. Definition courtesy Wireless Magazine.


PacketCable is a project managed by CableLabs on behalf of its member companies, PacketCable is a fast-track initiative aimed at developing interoperable interface specifications for delivering advanced, real-time multimedia services over IP-based packet channels carved out of two-way CATV cable plants. PacketCable is built on the infrastructure set by CableLabs Certified, previously known as DOCSIS (Data Over Cable Service Interface Specification), which sets standards for CATV modems and related network elements supporting high-speed Internet access over CATV networks. The PacketCable architecture is built around the NCS (Network-based Call Signaling) specification, which is a CATV-specific enhancement to MGCP (Media Gateway Control Protocol). MGCP is the de facto standard for multimedia call control between the traditional PSTN (Public Switched Telephone Network) and IP-based packet networks. PacketCable includes specifications for call signaling, QoS (Quality of Service) control, PSTN interconnection, security, network management, codec support, billing event messages, and network announcements. See also CableLabs, CableLabs Certified, MGCP, and NCS.

Packetized Video

First, read the definition of "Packet Switching." Then read the definition of "Packetized Voice" just below. The concept of packetized video is basically the same as that of packetized voice. A video camera feeds the signal into a codec, which converts the native analog signal into a digital format, and segments the data into data packets. The packets are sent across a packet network as a packet stream for reassembly by a codec on the receiving end of the transmission before presentation on a monitor. While packetized video performance is improving in quality through the application of increasingly sophisticated video compression techniques, it suffers from the same intrinsic packet-switching characteristics as does packetized voice. Namely, packet latency and loss. The result often is a video image which is less than pleasing. Note that voice and video are isochronous data, meaning that they are stream-oriented. In other words, the transmitting device must have regular and reliable access to the network. Further, the network must transport and deliver the data on a regular and reliable basis in order that a stream of information reach the presentation device. Such regular and reliable ingress, transport and egress of data results in a image of consistent quality. As packet-switched networks are not designed to support isochronous data communications, they generally are considered unsuitable for voice and video communications. Additionally, video is very bandwidth- intensive , thereby placing additional stress on packet-switched networks such as the Internet, which already is overloaded.

An example might help. Let's say that you are using an inexpensive ($200 or so) videoconferencing package consisting of a camera and software. Your friend has the same package. At a pre-arranged time, you place a call over the Internet to establish a video- conference. At two fps (frames per second) the videoconference goes along pretty smoothly, although both the video and voice quality are a bit rough. At some point, your friend turns his head quickly; at the same time, the Internet bogs down. The packet which contains the image of your friend's nose gets delayed or lost in the network. The video image of your friend now is missing a nose. Funny the first time, aggravating the second, maddening thereafter. The upside is that the videoconference is cheap, if not free, depending on your cost of Internet access. See also Packet Switching, Videoconferencing Internet and Isochronous.

Packetized Voice

First read the definition of "Packet Switching" just above. The idea is to digitize voice and, compress it, and then slice it up into packets and send those packets from the sender by various routes and assemble them as they get to the receiver. Packet switching for data makes sense. Packet switching for voice has not made sense because the voice is too sensitive to latency, or delay, especially the variable delay which is part and parcel of packet-switched networking. Recently developed software and DSP hardware, which employs sophisticated compression techniques has improved the ability to conduct "reasonable" quality packet voice conversations over the Internet. See Packet Switching, IP Telephony, TAPI 3.0.


Sprint's internal X.25 Packet Network.


Personal Communications Access System. PACS is a cellular system providing limited, regional mobility in a given area. It provides mobility between that of a cordless phone and a full-fledged cellular system. Originally developed by Bell Labs in the early 1980s, PACS is a comprehensive framework for the deployment of PCS and applies to both licensed and unlicensed applications. Now it is approved by the TIA and Exchange Carriers Standards Associations. Today's currently implemented versions of PCS are "up-banded" versions of the 900 MHz AMPS and GSM cellular standards.


Siemens' PBX And Computer Teaming. It defines protocols between Siemens PBXs and external computers.


  1. A pad is a device inserted into a circuit to introduce loss, i.e., to reduce the level of a signal. "Level" is a measurement of amplitude (signal power) at a specified point in a circuit known as a Transmission Level Point (TLP). "Loss" is the measurement of the decrease in amplitude between two TLPs, and is measured in decibels (dB). A pad may consist of any combination of inductors, resistors and capacitors. Pad or padding, as a verb, means to attenuate or reduce a signal, as in "to pad down the level". For example, we might say "the signal is 'hot', give me 5db of padding."

  2. Packet Assembler/Disassembler. A device that accepts characters from a terminal or host computer and puts the characters into packets that can be handled by a packet switching network. It also accepts packets from the network, and disassembles them into character streams that can be handled by the terminal or host. PADs generally are associated with X.25, an ITU-T Standards Recommendation for an access protocol used in older packet-switched networks. See also X.25.

  3. A concrete slab used as the foundation for a microwave radio tower or satellite dish.

  4. Portable Application Description, or PAD for short, is a data set that is used by share- ware authors to disseminate information to anyone interested in their software products.

Pad Characters

In (primarily) synchronous transmission, characters that are inserted to ensure that the first and last characters of a packet or block are received correctly. Inserted characters that aid in clock synchronization at the receiving end of a synchronous transmission link. Also called Fill Characters.

Pad Switching

A technique of automatically cutting a transmission loss pad into and out of a transmission circuit for different operating conditions.

PAF File

A British term. Post Office Address file, a publicly available data file that, when integrated with an application, links postcodes to full addresses. When using a PAF file, an agent can save time by entering only the postcode . The PAF file automatically inserts post town, street and country.


A chunk of information, like a document or file, on the Web. A hypermedia document as viewed through a World Wide Web browser. Pages are the way you make information available on the Web. They can contain text, black and white and color photographs, audio and video.

Page hits

A measure of the number of Web pages accessed at a particular site, or of the number of times a single page is accessed.

Page Mirroring

You're surfing the Internet. You come upon an Web site and find something you want to buy. It has a button that says, "To speak to an Agent, push here."

You do. An agent in a distant office calls you on another phone line. You're now both speaking to each other and your agent is also seeing the screen you're seeing. As you move to different screens (to different pages), the agent sees the same screens you are looking at. This is called page mirroring. At present, the technology won't allow the agent to move the pages which you see. Only you can move the screens.

Page Recall

A feature which allows subscribers to telephone a toll-free number to check messages at any time. Messages are stored in the IVR (Interactive Voice Response) device for a period of 99 hours.

Page Scan State

A Bluetooth term. A mode where a device listens for page strains containing its own device access code (DAC). A mode that a RemDev enters when advertising that a service is available.

Page State

A Bluetooth term. A mode that a LocDev enters when searching for services. The LocDev sends out a page to notify other devices that it wants to know about the other devices and/or their services.

Page train

A Bluetooth term. A series of paging messages sent over the baseband.

Page Zone

A local area in the office that can receive directed Page announcements independently of the remainder of the office.


A small one-way (typically) wireless receiver you carry with you. When someone wants you, they make your pager receiver alert you via a tone or a vibrator. They can activate your pager in a number of ways, including dialing your pager digits directly into a computer; calling your pager from a telephone; or the old, low-tech approach of giving your name and pager number to an operator who then punches out your numbers. Pagers have become small, cheap and very reliable. Monthly service costs have dropped and the area which you can be paged in most areas has widened dramatically. With most pagers you can be reached in most major metropolitan areas of the US. This minor miracle is accomplished through a combination of satellite and terrestrial radio networks; if the network can't reach you to deliver the page, it will store the message until you can be reached. Some pagers also display small alphanumeric messages-like phone numbers to call and names of babies born; this capability is known as SMS (Short Message Service). Many pagers and pager networks now include an "acknowledgment" feature, which allows you to press a button to acknowledge the receipt of the page through two-way communications capability. All this has made the pager far more useful. Some multi-function devices incorporate pagers into cellular phones. See also Paging and SMS.

Pager Codes

Forget the phone. Forget the PC. Pagers are teenagers' new communication tools of choice. Wondering what your kid is receiving? Here are the secret codes, according the September 1997 Seventeen Magazine and Danielle Cioffi.

007 ” I've got a secret. 143 ” I love you. 07734 ” Hello (upside down). 55 ” Let's go for a drive. 2468 ” Who do we appreciate? You. 13 ” I'm having a bad day. 10-4 ” Is everything ok? 2-2 ” Shall we dance ? 666 ” He's a creep. 90210 ” She's a snob. 9-5 ” Time to go home. 121 ” I need to talk to you alone. 100-2-1 ” Bad odds. That's not likely.


  1. To send a message to someone who is somewhere, but where we don't know. Paging can be done with a little " beeper " carried in her purse or on his belt. Paging can also be done through speakers in phones or from speakers in the ceiling. Most phone systems offer a paging channel access. You dial that number and page your party. The system comes "live" and your voice is heard everywhere. Similar to the stuff they have at airline terminals. Paging systems as an accessory to phone systems always cost extra. They're one of the most valuable features on a phone system. Don't skimp, however, on the quality of the speakers or the power of the paging system. If you do, your system will sound awful and people will not use it. See Pager.

  2. A Bluetooth term. A paged device is typically contacted by a paging device to establish a communication link. See acceptor.

Paging Access, Rapid

Your attendant and you or anybody else with an extension off your PBX can make a page (access the paging equipment) by pushbuttoning one or several digits. Sometimes you can dial one several numbers for different paging alternatives. One number gives you the tenth floor. One number gives you the fourth floor, etc. And one number to page everyone ” also called an "ALL CALL" page. See also Rapid Paging Access.

Paging By Zone

By dialing the appropriate access code, any phone is able to selectively page "groups" of pre designated phones or speakers.

Paging Channel

PCH (from Paging CHannel). Specified in IS-136, PCH carries signaling information for set up and delivery of paging messages from the cell site to the user terminal equipment. PCH is a logical subchannel of SPACH (SMS (Short Message Service) point-to-point messaging, Paging, and Access response CHannel), which is a logical channel of the DCCH (Digital Control CHannel), a signaling and control channel which is employed in cellular systems based on TDMA (Time Division Multiple Access). The DCCH operates on a set of frequencies separate from those used to support cellular conversations. See also DCCH, IS-136, Paging, SPACH and TDMA.

Paging Code Call Access

A feature of the ROLM Attendant Console which offers direct, one-touch access to the paging or code call features.

Paging device

A Bluetooth term. A paging device is typically attempting to establish a communication link with other devices. See initiator.

Paging Procedure

A Bluetooth term. With the paging procedure, an actual connection can be established. The paging procedure typically follows the inquiry procedure. Only the Bluetooth device address is required to set up a connection. Knowledge about the clock will accelerate the setup procedure. A unit that establishes a connection will carry out a page procedure and will automatically be the master of the connection.

Paging Speakers

Speakers in the telephone. Also external units located in ceilings, on walls, etc.

Paging Total System

Upon dialing the appropriate special code, any station may make a paging announcement through all the loudspeakers.

Paid Call

The usual type of a toll telephone call automatically billed to the calling telephone number.

Paid Hours

A call center term. The time that an employee is either on duty handling calls, doing other work, in meetings, etc., or on a paid schedule exception, such as an excused absence.

Paid Search

A fast-growing segment of the online advertising market in which advertisers pay to be listed in Web search results. For example, I search for folding bicycles. When the results of my search come up, they also bring up the web sites for those suppliers of folding bicycles who paid to show up, should someone search for folding bicycles. This area of paid searching is a fast-growing area, since such advertising really works ” or at least that's what advertisers have discovered .


In military terms, painting means that your aircraft have been targeted for ground- based air defense ground-to-air missiles. The term is used in Iraq where coalition forces regularly fly surveillance missions and their planes are often " painted " by the Iraqi air defense radars.


Someone with a less-than -glamorous, entry-level computer graphics job. A paintmonkey may spend months on a nanosecond of digitized film footage, painting mattes, or doing monotonous touch-ups.


The two wires of a circuit. Those which make up the subscriber's loop from his office to the central office.

Pair Gain

The multiplexing of x phone conversations over a lesser number of physical facilities. Pair gain usually refers to electronic systems used in outside plant ” from the central office to the subscriber's premises. In "pair gain" you might do something as simple as take one pair of wires and carry two conversations on it. You might also take two pairs and carry 128 conversations. "Pair gain" is actually the number of conversations you get minus the number of wire pairs used by the system. Lucent Technologies has various subscriber pair gain devices called "SLC" (pronounced "slick" and standing for Subscriber Loop Carrier Systems). Other companies, like Rockwell, have comparable systems. The more circuits these devices produce, i.e. the more cable pairs they save you, the more they cost. The cost of subscriber pair gain equipment ” like all electronics ” has been dropping in recent years, reducing the phone company's need to install outside cable and thus making better use of the presently installed cable. T-1 is a type of subscriber pair gain equipment.

Pairable Mode

A Bluetooth term. A device that accepts pairing . is said to be in pairable mode. The opposite of pairing mode is non-pairable mode. paired device A device with which a link key has been exchanged (either before connection establishment was requested or during connecting phase).

Paired Cable

A cable in which all conductors are arranged in twisted pairs. This form of cable is the most common for communications.


A Bluetooth term. The creation and exchange of a link key between two devices. The devices (LocDev and RemDev) use the link key for future authentication when exchanging information. Pairing is also called an association between a LocDev and a RemDev based on a common link key. The link key is also referred to as a bond. Pairing can also establish a link by the user entering a PIN which is authenticated by the device providing the service.

Pairs in Metal Foil



  1. Public Access Line. Also called a COCOT, if you live outside of US West territory. A line that is tariffed to be attached to a pay phone. There are two basic flavors, "smart" and "basic" (or dumb). Smart lines may be connected to dumb phones, and offer features such as coin signalling. Basic lines may be connected to smart phones, and the phone does all the work. Between the phone and the line, somebody has to have some intelligence. I first heard about this from one of my customers, a pay phone provider that puts up phones around town and pays commissions to the building owners . The service is tariffed by US West as a Public Access Line. (With multiple providers such as this one, anxious to pay you a percentage on a pay phone installed at your location, it's pretty silly to pay Bell for a pay phone).

  2. Programmable Array Logic.

  3. Proprietary ALgorithm. A designation for a privately designed and owned intelligence- based electronic method for performing a task (such as voice compression).

  4. Phase Alternate Line. PAL is the format for color TV signals used in the United Kingdom, West Germany, Holland, much of the rest of western Europe, several South American countries, some Middle East and Asian countries, several African countries, Australia, New Zealand, and other Pacific island countries. PAL inverts the phase of the color signal 180 degrees on alternate lines, hence the term Phase Alternate Line. It was invented in 1961 and is used in England and many other European countries . With its 625-line scan picture delivered at 25 frames/second (primary power 220 volts ), it provides a better image and an improved color transmission compared to the US system which is called NTSC, which uses interlaced scans and 525 horizontal lines per frames at a rate of 30 frames per second. SECAM is used in France and in a modified form in Russia. SECAM uses an 819-line scan picture which provides better resolution than PAL's 625-line and NTSC's 525. All three systems are not compatible. You cannot view an Australian or English videotape on a US TV. Well, at least, you couldn't until recently when a handful of manufacturers started making PAL/NTSC NTSC/PAL Video Cassette Recorder decks which will play and record in all formats. These VCRs are now very popular in both Europe and the US. See NTSC, mPAL-M and PVR.

  5. Paradox Application Language. A programming language used in PDP (Programmed Data Processor) computers developed and marketed by Digital Equipment Corporation in the 1970s. See also PDP and PDP-11.


A modified version of the phase- alternation -by-line (PAL) television signal standard (525 lines, 50 hertz, 220 volts primary power), used in Brazil. See also NTSC, PAL, SECAM.


In some programs, a palette is a collection of drawing tools, brush widths, line widths and colors. In other programs it is the part of the color lookup table that determines the number and type of colors that will be displayed on the screen.


See pseudo Automatic Location Identification.

Newton[ap]s Telecom Dictionary
Newton[ap]s Telecom Dictionary
ISBN: 979387345
Year: 2004
Pages: 133

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