P

phone-centric connection

A connection that consists of a single POTS line in which the computer is connected to the switch through the desktop phone set. Compare computer-centric connection.

Plain Old Telephone Service (POTS)

Basic telephony service supplying standard single-line telephones, telephone lines, and access to the public switched network.

point-to-point protocol (PPP)

A communications protocol that allows a computer to connect to other computers over a standard dial-up telephone line using a high-speed modem.

POTS

See Plain Old Telephone Service (POTS).

PRI-ISDN

See Primary Rate Interface (PRI-ISDN).

Primary Rate Interface (PRI-ISDN)

A type of ISDN service that offers 23 B channels at 64 Kbps and one D channel at 64 Kbps (23B+D). In Europe, PRI provides for 30 B channels and two D channels (30B+2D). See also Basic Rate Interface (BRI-ISDN).

private branch exchange (PBX)

A private telephone switching system, usually located on a customer's premises with an attendant console. The PBX is connected to a common group of lines from one or more central offices to provide service to a number of individual phones, such as in a hotel, business, or government office. PBXs often use proprietary digital-line protocols, although some are analog based.

provisioning

The combination of device and service options that make up an ISDN line. When you order your ISDN line, the telephone company provisions the line, that is, it configures your ISDN service according to the physical capabilities of the switch, as well as the options you choose.

public switched telephone network (PSTN)

The local analog telephone network, which provides 3.1 kHz voice-grade quality of service (its bearer mode).