The analogue phone line problem
Older telephone entry systems were built to dial out over an analogue copper line. When a property moves to VoIP, fibre or a modern PBX, the signalling those units expect is no longer present and they simply stop dialling — even though the hardware is undamaged and everything else about the gate works.
This catches out a great many communities, usually months after the phone change, because nobody connects the two events. The fix is normally a cellular module rather than a whole new system, which is considerably cheaper than the replacement often quoted.












