"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"

PACKET. In data communication, a sequence of binary digits, including data and control signals, that is transmitted and switched as a composite whole.

PACKET FORMAT. The structure of data, address, and control information in a packet.

PACKET SWITCHING. The process of routing and transferring data by means of addressed packets so that a channel is occupied during the transmission of the packet only, and upon completion of the transmission the channel is made available for the transfer of other traffic.

PARALLEL PORT. A port through which two or more data bits are passed simultaneously, such as all the bits of an 8-bit byte, and that requires as many input channels as the number of bits that are to be handled simultaneously.

PHYSICAL TOPOLOGY. The physical configuration, i.e., interconnection, of network elements, e.g., cable paths, switches, concentrators.

PRINTED CIRCUIT BOARD. A flat, insulating surface upon which printed wiring and miniaturized components are connected in a predetermined design and attached to a common base. [PWB]

PROTOCOL. A formal set of conventions governing the format and control of interaction among communicating functional units. [Protocol Dictionary]

PULSE-CODE MODULATION (PCM). A modulation system in which the standard values of a quantized wave are indicated by a series of coded pulses. PCM Code Definitions

PULSE DURATION (PD). The period of time during which a pulse is present.

PULSE WIDTH. Duration of time between the leading and trailing edges of a pulse.