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Jargon Buster
The du Pré Jargon Buster found the following for - PNos A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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Term
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Explanation
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| PA | A commonly used term. Per Annum | |
| PABX | Private Automatic Branch Exchange. A switching device for routing telephone calls to the relevant desk within an organisation | |
| Packet Switching | The technique of switching data in a network where individual blocks or ‘packets’ of data of controlled size and format are accepted by the network and routed to their destination. The sequence is maintained and the destination is determined by exchanging control packets between the originating terminal and the network before transfer starts - see PSDN | |
| PAD | Packet Assembler / Disassembler. A device used in an X.25 network to permit terminals which do not have an interface suitable for direct connection to a packet-switched network to access such a network | |
| PAP | Password Authentication Procedure. A procedure used to validate a connection request. After the link is established, the requestor sends a password and an id to the server. The server either validates the request and sends back an acknowledgement, terminates the connection, or offers the requestor another chance. | |
| Parallel Port | A socket which passes information at 8 bits at a time in ‘parallel’. Therefore faster than a serial port. Typically used to connect a computer to a printer | |
| Parent Extension | see Daughter Extension | |
| Parity Checking | A technique of error detection in which one bit is added to each data character so that the number of logic one bits per character is always even, or always odd, or always a mark condition, or always a space condition | |
| Parity memory | Memory that has an extra bit, dedicated to checking for errors | |
| Passive Bus | see So-bus | |
| PBX | Private Branch Exchange. The generic term given to a telephone system on a customer’s premises | |
| PC | i) Personal Computer ii) see Private Circuit |
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| PC Card | The hardware that fits into an expansion slot of a computer to enable it to act like an ISDN terminal | |
| PC-DOS | IBM's version of DOS, derived from Microsoft's DOS | |
| PCI | i) Peripheral Component Interconnect. Intel’s own local-bus technology designed to allow PC manufacturers to build PCs on which all peripherals can be connected to the processor via the local-bus. Has replaced ISA on the majority on new PCs ii) Pre-Connection Inspection. Used to be an Oftel requirement for BT to ensure a telephone system was installed correctly to BS6506 and BS6701, as well as meeting the conditions laid down in the telephone system’s specific PXML, before connection was allowed to the network |
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| PCM | Pulse Code Modulation of voice frequencies | |
| PCMCIA | Personal Computer Memory Card International Association | |
| PCMCIA slot | Personal Computer Memory Card International Association slot, accepts an IC card. Type I takes a straightforward memory card. Type II accepts a range of network and modem cards. Type III, twice as thick as type II, offers more possibilities | |
| PCU | Protocol Converter Unit. Typically used by BT to convert DASS2 to I.421 in a subscriber's premises | |
| PDH | Plesiochronous Digital Hierarchy. A European transmission designed for 32 x 64Kbit/s framing format. One channel is used for patterns and management, and the other 31 for the payload. In telephony systems, another of the 64k channels is used for signalling, leaving 30 for payload. Hence, line speed is 2.048Mbit/s | |
| PDI | A BT SMDS term. Protocol Data Unit | |
| PDN | Private Data Network | |
| PDS | Premises Distribution System. An unshielded twisted pair wiring scheme that supports data and voice communications developed by AT&T, and renamed Systimax. Fibre structured wiring is also supported within PDS | |
| Peer-to-peer | A network arrangement where each computer is of a similar power, and communication between devices is on an equal footing. There is no host / terminal or master / slave relationship. Any of the PCs can hold the applications software and data and control the network traffic | |
| Pentium | Intel’s processor chip. Their previous chips were the 80386 and 80486 | |
| Pentium II | A more recent processor from Intel. Provides speeds of 233MHz and 266MHz, uses RISC technology | |
| Pentium Pro | Intel’s processor designed specifically for 32-bit applications. Works well with NT workstations and servers, where its power is really utilised | |
| Perimiter Network | see Perimiter Network | |
| Pertain | i) Pertai´n - belong as part, appendage, or accessory, (to); be appropriate (to); have reference or relate (to). [ME, f. OF partenir f. L per (tinere = tenere hold)] ii) Pertai´n (a du Pré Belarus expression) - Can be used as a verb, noun, or colloquial substitution for any obvious verb, adverb, noun or euphemism. Verb: deliver or be on the receiving end of unnecessarily loquacious irrelevant drivel. Noun: as in "I’ve just received a vicious pertain". Colloquial Substitution: as in “it’s raining cats & pertains outside”, or, “you go straight up the high street & it’s the third pertain on the left.” |
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| Physical Layer | The lowest layer of the OSI reference model. Defines the physical and electrical characteristics of the interface to the network and provides a transparent transmission path for the information across the chosen medium | |
| Piggy-backing | Where one telephone system (typically a key-phone system) is connected by its exchange line ports to the extension ports of another telephone system | |
| PING | Packet Internet Groper. A utility used to determine whether a specific IP address is accessible. It works by sending a packet to the specified address and waiting for a reply. PING is used primarily to troubleshoot Internet connections | |
| Pipe | Slang term for an ISDN circuit | |
| PKI | Public Key Infrastructure | |
| PMBX | Private Manual Branch Exchange. The old, manual version of a PABX | |
| PMR | Private Mobile Radio, for use on 446MHz which does not require a licence | |
| PN | see Presentation Number | |
| POA | A Payphone term – Pay On Answer | |
| Point | A telephony ot data outlet | |
| Point to Multi-point | Typically, an ISDN term, indicating an ISDN circuit has been connected direct to a number of Terminal Equipments on an So-bus, without the involvement of a switching device such as a telephone system or router | |
| Point to Point | i) A single connection from one point to another. Typically, to connect two pieces of equipment, networks, or premises ii) An ISDN term. Where a routing device, such as a telephone system or router, is connected to an ISDN circuit iii) A Frame Relay term. Point to Point Protocol |
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| Poly Jelly Filled cable | Cable which has a thick jelly within it, for waterproofing purposes. Hence, used for external cabling | |
| POP3 | Post Office Protocol No 3. An Internet post box or pigeon hole for a user to access for his mail | |
| Port | The exit and entrance point for information going out of and coming into a computer or other data communications device | |
| POT | Perfectly Ordinary Telephone – a 2-wire analogue telephone – see Message Waiting | |
| Power-Fail | A telephone system must have 20% of its PSTN exchange lines able to be used during power failure. This is usually by parallel connection direct onto the exchange lines using POTs, or, some systems have the facility of various extensions automatically being connected direct to exchange lines | |
| PowerPC | A processor based on RISC architecture. Commonly on Apple computers | |
| ppm | i) Pages per minute. The rate at which a printer can print ii) In telephony terms, the Pence Per Minute charge for a telephone call |
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| pps | Pulses Per Second - see Dial Pulse | |
| pq | A commonly used term. Per Quarter | |
| PRA | An ISDN term. Primary Rate Access. Refers to a 30 channel ISDN circuit (30B + D) commonly known in Europe as an E1 circuit. In the USA, PRA is a 23 channel circuit (23B + D) and is known as a T1 circuit | |
| Presentation Layer | Layer six in the OSI reference model. Fulfils the requirement for identifying and agreeing the common syntax (grammar) to be used between two applications | |
| Presentation Number | A BT Digital Select Service | |
| PRI | An ISDN term. Primary Rate Interface – see PRA | |
| Primary Socket | see Master Socket | |
| Private Circuit | A general term for a permanently connected circuit for private telecommunications or data use, joining two geographic locations, often rented from a PTO such as BT | |
| Private Key | In cryptography, a Private Key (or Secret Key) is an encryption/decryption key known only to the party or parties that exchange secret messages. In traditional secret key cryptography, a key would be shared by the communicators so that each could encrypt and decrypt messages. The risk in this system is that if either party loses the key or it is stolen, the system is broken. A more recent alternative is to use a combination of a Public Key and a Private Key. In this system, a public key is used together with a private key. | |
| Private Wire | see Private Circuit | |
| Processor | The PC’s ‘engine’. Sitting inside the CPU. Also referred to as the microprocessor, chip or microchip. For example, the Pentium | |
| Proprietary | An item which can only be used with a specific make or model of a system. Typically, Samsung DCS keyphones which can only be used with Samsung equipment. Or, an operating system which can only be used in one brand of machine and which only supports software written for that system. The opposite of Vendor Independent | |
| Protocol | Refers to the set of rules which govern the format, sequencing and error control of messages exchanged between communication entities in a network | |
| PRS | A BT term. Premium Rate Services, provided by dialling codes which are charged at much higher rates than standard calls | |
| PSDN | The Packet Switched Data Network. A mixed analogue and data network which connects data terminals together. Information is sent in electronic packets which are labelled with the receiver’s address. Charges are made according to the volume of information sent, rather than the length of time the line is open. For this reason, it is ideally suited to applications where a small amount of information is being sent over a long period of time | |
| PSDPN | A private version of the PSDN | |
| PSS | Packet SwitchStream Service. The BT X.25 public switching network | |
| PSTN | Public Switched Telephone Network. The analogue network originally established over a hundred years ago and to which the vast majority of subscribers are currently attached. Used for voice and data transmission. However, data speeds are limited to less than 64Kbit/s, and in practice to between 9,600bit/s and 56,000bit/s | |
| PSTN Line voltage | The voltage on a PSTN exchange line or DEL is 50 volts DC | |
| PSTN Ringing voltage | The ringing voltage on a PSTN exchange line or DEL is 125 volts AC | |
| PSU | Power Supply Unit. Normally for converting mains power to other voltages | |
| PTNX | Private Telecoms Network Exchange. A new ISDN telephony term to break away from the tradition that a PABX is primarily offered for voice services | |
| PTO | Public Telecommunications Operator. An organisation licensed to instal its own telecommunication transmission networks and operate international facilities | |
| PTT | i) Post, Telegraph and Telephone is another, yet old, name for a PTO ii) Push To Test |
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| Public Key | A Public Key is a value provided by some designated authority as a key that, combined with a private key derived from the public key, can be used to effectively encrypt and decrypt messages and digital signatures. The use of combined public and private keys is known as asymmetric encryption. A system for using public keys is called a Public Key Infrastructure. | |
| Pulse | see Dial Pulse | |
| Pulse Code Modulation | Pulse Code Modulation. A method of encoding analogue signals to digital, by taking 8000 samples per second and encoding each into 8 bits, giving a bandwidth of 64Kbit/s. Provides very high quality. Founded by Alec Reeves in 1937, and now used for telephony transmission and switching purposes. Abbreviated to PCM | |
| Pure IP Telephony | see Pure IPT | |
| Pure IPT | Telephony which connects to the Internet using xDSL circuits. In Pure IPT, extension connect to the LAN, and the LAN connects to a Router. Proof of Pure IPT is where no internal telephone system or CPU exists |
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| PVC | Permanent Virtual Circuit | |
| PW | An abbreviation for Private Wire. Now renamed Private Circuit or PC | |
| PXML | Private Exchange Master List. Telephone systems used to be issued with a PXML upon approval by the BABT. The PXML listed every piece of its equipment, software levels and its approved features and facilities. Systems were approved as PABX, KTS, or ACD. In 1996, the PXML was replaced by the TEC Annex, and in April 2001 by the SDC |