1A2 Key System - Advantages

Advantages

The 1A2 system is uncommon today, but some very large installations are still in use due to the high cost of replacing them. There are also several systems in use by collectors of 'vintage' telephone equipment. 1A2 systems are also very popular, still, with radio stations. This is because, being analog, they are easily patched into the studio equipment for putting callers on the air.

Unlike most electronic key systems or PBX's, 1A2 systems remain partially functional in the event of a local power failure. The telephones themselves are still able to make and receive calls, assuming the phone company's central office stays alive, but the system is unable to provide any sort of visual (lamps)or intercom (buzzers) signaling during a power outage. The 'Hold' function and intercom services would also be inoperable. Central office powered ringers will continue to function and by designating one telephone ringer per line it is possible to identify what line is ringing by what telephone is ringing. Despite the fact that the 1A2 systems have widely been replaced by more recent electronic key systems or PBX's, the simple and modular design of the 1A2's components provide a degree of versatility and reliability that few of its modern successors can match. This is why 1A2 equipment may be seen in service in places like emergency operations centers, and older police and fire stations.