It was also referred to as the 6B intercom system. 100% solid-state replacement for the 6A and mighty sophisticated for the purpose. It had features such as call forwarding and call waiting (a bit overkill for an intercom system). It supported single line sets, but required the ringer to be on a separate pair. It also emulated full 1A2 functionality on key sets with intercom buttons (hold, private talk path, etc.) without the need for a separate line card. It allowed dial access to outside lines, so in a way it was similar to a PBX. I only encountered one in this area that had been abandoned in the mid 1980's, so I removed it and used it at home for a while. It wasn't nearly as popular with Bell Atlantic as Tone Commander's ML-8000.

Ed Vaughn, MBSWWYPBX