1 Comments Posted by John j444rose@yahoo.com

Yes, that is exactly what it is, probably connected to a PBK675 power booster amplifier....working on those public address, nurse call and intercom systems in my early years was lots of interesting fun....i wish i could go back to those days....recently just discarded all my old service manuals which i refused to get rid of for a few decades...needed the room in my garage for other crap....