Appendix C: Glossary and Acronyms

NT Network Termination

A device connecting the customer's telephone or data equipment to the local ISDN exchange carrier's line. NT devices are connected to TE devices.

PBX Private Branch Exchange

A smaller version of a phone company’s large central switching office. Example: Asterisk.

PCI peripheral component interconnect

A standard bus used in most computers to connect peripheral devices.

POP Point of Presence

The physical connection point between a network and a telephone network. A POP is usually a network node serving as the equivalent of a CO to a network service provider or an interexchange carrier.

POTS Plain Old Telephone Service

The public switched telephone network (PSTN) is the network of the world's public circuit-switched telephone networks. Originally a network of fixed-line analog telephone systems, the PSTN is now almost entirely digital, and now includes mobile as well as fixed telephones.

PPPPoint-to-Point Protocol

Type of communications link that connects a single device to another single device, such as a remote terminal to a host computer.

Digium, Inc.

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