Exactly. It is sort of like 1A2, more like Comkey 718/1434/2152. The line cut down is T, R, A and L. There's a common ground for the lamps. There is no ringer in the set, just an amplifier and speaker that repeats the tone that is sent in over the pair that feeds audio into it (I believe audio is on the yellow/orange and power for the amplifier is on the yellow/slate @ 24VDC). I've wired these into existing 1A2 systems, but it is no walk in the park. I used a 455A KTU from a Comkey 718 system to provide the tone ringing signal.


Ed Vaughn, MBSWWYPBX