| Glossary: P |
| P/AR |
Peak-to-Average Ratio
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| Packet assembler/disassembler (PAD) |
A device that accepts characters from a terminal or host computer. It then puts the characters into packets that a packet switching network can handle. It also accepts packets from the network then disassembles them into character streams that the terminal or host can handle.
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| Packet Switched Public Data Network (PSPDN) |
Packet oriented public network usually based on X.25.
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| Parity check |
A process for detecting data bits that changed during transmission.
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| Path |
End-to-end transport of a service usually consisting of multiple lines and sections. (SONET)
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| PCM |
See Pulse Code Modulation. Also an acronym for Partition Control Master (number)
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| PCO |
Plant Control Office
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| PDS |
Program Documentation Standard
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| PDU |
Protocol Data Units
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| Percent error-free seconds |
The percentage of elapsed test seconds that do not contain errors.
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| Performance monitoring |
The collection of data on either a part-time or full-time basis so that the overall efficiency of a circuit may be determined.
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| Permanent virtual circuit (PVC) |
A virtual circuit set up by the provider that establishes a dedicated point-to-point connection between two users.
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| PFA |
Private Facility Access
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| PGTC |
PairGain Test Controller
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| PH |
Phase Hit
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| PHTh |
Phase Hit Threshold
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| PIC |
Port Interface Card
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| PID |
Process Identification or Private (or Password) Identifier
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| Plain old telephone service (POTS) |
Voice-grade telephone service.
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| PLAR |
Private Line Automatic Ringdown
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| PLNK |
Point Link
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| PMC |
Phantom Maintenance Connector
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| PMNIU |
Performance Monitoring Network Interface Unit
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| PNNI |
Private NNI
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| Point of presence (POP) |
The physical access location within a LATA of a long-distance and/or inter-LATA common carrier. The point to which the local telephone company terminates subscriber's circuits for long-distance dial-up or leased-line communications.
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| Point-to-point |
A circuit that interconnects two points directly where there are generally no intermediate processing nodes computers or branched circuits although there could be switching facilities; a type of connection such as a phone-line circuit that links two and only two logical entities.
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| POSIX |
Portable Operating System Interface (IEEE)
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| PPP |
Point-to-Point Protocol
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| PPS |
Pulse Per Second
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| PPSN |
Public Packet Switched Network
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| PQI |
Performance Quality Index
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| PRBS |
Pseudorandom Bit Stream or Binary Sequence
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| PRI |
Primary Rate Interface
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| Private line |
A customer leased circuit not interconnected with the public switched telephone network for the customer's exclusive use. The private line provides transmission of voice teletypewriter data television etc.
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| Program circuit |
A voice-frequency circuit which has been equalized to handle a wider range of frequencies than what ordinary speech signals require.
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| Protocol Vital Signs® (PVS®) |
A systematic method of analysis and display of protocol operational parameters to aid in determining the cause of performance degradation.
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| PSD |
Power Spectral Density
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| PSDS |
See Public Switched Digital Service.
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| PSTN |
See Public Switched Telephone Network.
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| PSU |
Power Supply Unit
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| PTSU |
Protection Transmission Switching Unit
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| PTT |
Post Telephone and Telegraph Network
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| Public switched digital service (PSDS) |
A service that provides alternate voice and data on a 2-wire user loop.
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| Public switched telephone network (PSTN) |
A direct distance dialing telephone network that is available for public use. The network is an integrated system of transmission and switching facilities signaling processors and associated operations support systems that is shared by customers.
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| Pulse code modulation (PCM) |
The process that samples quantizes and codes the modulating analog signal into digital bit stream.
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| PVP |
Permanent Virtual Path
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