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Appendix D: Glossary and Acronyms
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
Standard phone service over the public switched telephone network
(PSTN). This service provides analog bandwidth of less than 4 kHz.
PPP
point-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.
PSTN
public switched telephone network
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
