Digium, Inc.
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Appendix C: Glossary and Acronyms
DS1
Digital Signal, Level 1
1.544 Mbps in North America (T1) and Japan (J1) -up to 24 voice
channels (DS0s), 2.048 Mbps in Europe (E1) - up to 32 voice channels
(DS0s). DS1/T1/E1 lines are part of the PSTN.
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 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.
