Appendix C: Glossary and Acronyms
full duplex
Data transmission in two directions simultaneously.
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
(ITUT) for an algorithm designed to transmit and receive mulaw PCM
voice and Alaw at a digital bit rate of 64 kbps.
G.723.1
A recommendation by the Telecommunication Standardization Sector
(ITUT) for an algorithm designed to transmit and receive audio at 6.3
kbps or 5.3 kbps.
G.729a
A recommendation by the Telecommunication Standardization Sector
(ITUT) for an algorithm designed to transmit and receive audio at 8
kbps.
H.323
A recommendation by the Telecommunication Standardization Sector
(ITUT) for multimedia communications over packetbased networks.
Digium, Inc.
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