Digium, Inc.
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Appendix C: Glossary and Acronyms
DS3
Digital Signal, Level 3
T3 in North America and Japan, E3 in Europe. Up to 672 voice channels
(DS0s). DS3/T3/E3 lines are not part of the PSTN
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 voice channels (DS0s).
E3
The European equivalent of North American T3, transmits data at 34.368
Mbps, up to 512 voice channels (DS0s). Equivalent to 16 E1 lines.
EMI
Electromagnetic Interference
Unwanted electrical noise present on a power line
full duplex
Data transmission in two directions simultaneously.
FXO
Foreign Exchange Office
Receives the ringing voltage from an FXS device.
FXS
Foreign Exchange Station
Initiates and sends ringing voltage.
VoIPon www.voipon.co.uk [email protected] Tel: +44 (0)1245 808195 Fax: +44 (0)1245 808299
