Telephone signaling interfaces
From Wikipedia, the free encyclopedia
There are many interface standards between analog telephone central office equipment and the subscriber's premise. Single voice paths generally include analog audio connections, either a two-wire circuit or four-wire circuit plus signaling paths to indicate call progress and status information, such as ringing, answer supervision, etc. Some of the known interface types are
- FXO foreign exchange office
- FXS foreign exchange station
- DPO dial pulse originate
- DPT dial pulse terminate
- E and M signaling
- KS Kewlstart
- Loop start
- Ground start
