Digium, Inc.
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Appendix C Glossary and Acronyms
FXO
Foreign Exchange Office
Receives the ringing voltage from an FXS device. Outside lines are
connected to FXO ports.
FXS
Foreign Exchange Station
Initiates and sends ringing voltage. Phones are connected to FXS ports.
G.711
A recommendation by the Telecommunication Standardization Sector
(ITU-T) for an algorithm designed to transmit and receive mulaw PCM
voice and A-law at a digital bit rate of 64 kbps.
G.723.1
A recommendation by the ITU-T for an algorithm designed to transmit
and receive audio at 6.3 kbps or 5.3 kbps.
G.729a
A recommendation by the ITU-T for an algorithm designed to transmit
and receive audio at 8 kbps.
H.323
A recommendation by the ITU-T for multimedia communications over
packet-based networks.
HDLC
High-Level Data Link Control
A bit-oriented synchronous data link layer protocol developed by the
International Organization for Standardization (ISO).
