E and M
Created by: jht2,Last modification on Fri 14 of Oct, 2005 [07:38 UTC]
E&M is a type of signaling using on analog telephone trunks.
E&M connections use an E and M wire in addition to the wires to carry the voice.
Since the voice can use either 2 wires or 4 wires, the total numbers of wires used on an E&M circuit is either 4 or 6.
The E wire was originally called the Ear lead and the M wire was originally called the Mouth lead.
Signals sent on these wire are typlically -48 volts, ground, and open.
E&M connections use an E and M wire in addition to the wires to carry the voice.
Since the voice can use either 2 wires or 4 wires, the total numbers of wires used on an E&M circuit is either 4 or 6.
The E wire was originally called the Ear lead and the M wire was originally called the Mouth lead.
Signals sent on these wire are typlically -48 volts, ground, and open.
See Also
- Understanding and Troubleshooting Analog E&M Start Dial Supervision Signaling - Cisco Document
- Multitech - one of the few makes of ATAs and gateways with E&M support.
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