Search Results for: Signalling apparatus parts
] in the united states when the integrated services digital network (isdn) basic rate interface (bri) was introduced, followed by cellular telephone systems, and voice over ip (voip). pots remains the basic form of residential and small business service connection to the telephone network in many parts
range of – hz call-progress tones , such as dial tone and ringing tone pulse dialling and dual-tone multi-frequency signaling (dtmf) borscht functions: battery feed (b), over-voltage protection (o), ringing (r), signaling (s), coding (c), hybrid (h), and test (t) loop start, ground start and e&m signalling...
https://en.wikipedia.org/wiki/Plain_old_telephone_service