ALLO PRI Gateway
User Manual V2.0
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9. Appendix B:
Glossary and Acronyms
DS0
Digital Signal, Level 0
A voice grade channel of 64 kbps. The worldwide standard speed for
Digitizing voice conversation using PCM (Pulse Code Modulation).
DTMF
Dual Tone Multi-Frequency
Push-button or touch tone dialing.
E1
The European equivalent of North American T1, transmits data at 2.048
Mbps, up to 32 channels (DS0s).
E3
The European equivalent of North American T3, transmits data at 34.368
Mbps, up to 512 channels (DS0s). Equivalent to 16 E1 lines.
EMI
Electromagnetic Interference
Unwanted electrical noise.
Full duplex
Data transmission in two directions simultaneously.
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 ulaw PCM voice and A-law at a digital bit rate of 64 kbps.
G.723.1
A recommendation by the Telecommunication Standardization Sector (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 Telecommunication Standardization Sector (ITU-T) for an algorithm
designed to transmit and receive audio at 8 Kbps
HDLC
High-Level Data Link Control
A bit-oriented synchronous data link layer protocol developed by the International Organization
for Standardization (ISO).
iLBC
internet Low Bit rate Codec
A free speech codec used for voice over IP. It is designed for narrow band speech with a
payload bit rate of 13.33 kbps (frame length = 30ms) and 15.2 kbps (frame length = 20ms).
PBX
Private Branch Exchange
A smaller version of a phone company’s large central switching office. Example: Asterisk.
POTS
Plain Old Telephone Service
