Glossary

packet-switched network - A network that allows a message to be broken into small "packets" of data that are sent separately by a source to the destination. The packets may travel different paths and arrive at different times, with the destination sites reassembling them into the original message. Packet switching is used in most computer networks because it allows a very large amount of information to be transmitted through a limited bandwidth.

passive optical network (PON) - a fiber-based transmission network containing no active electronics.

peripheral - An external device that increases the capabilities of a communication system.

plain old telephone service (POTS) - An acronym identifying the traditional function of a telephone network to allow voice communication between two people across a distance. In most contexts, POTS is synonymous with the public switched telephone network (PSTN).

point of presence (POP) - The physical point of connection between a data network and a telephone network.

PON - See passive optical network.

POP - See point of presence.

Postal, Telegraph and Telephone (PTT) - The generic European name usually used to refer to state-owned telephone companies.

POTS - See plain old telephone service.

POTS splitter - A device that uses filters to separate voice from data signals when they are to be carried on the same phone line, required for several types of DSL service.

PRI-ISDN - See primary-rate ISDN.

primary-rate ISDN (PRI-ISDN) - The primary rate ISDN interface provides 23 64 Kb/s channels (called B channels) to carry voice or data and one 16 Kb/s signaling channel (the D channel) for call information.

PTT - See Postal, Telegraph and Telephone. public switched telephone network (PSTN) The worldwide communications network that carries phone calls and data.