We have 5 Bogen TAM-Bs distributed around our campus that interface to 20 year old amplifiers and they have proved to be very successful. Basically they take our VG248 interface and allow them to communicate to the amplifiers.

There are settings on the TAM-B that assist with max silence, etc.

While we don't have a TPU 15A, I believe this is just the amplifier that provides signal to the speakers. You would hook up the "Pager Tip/Ring" on the TAM-B to the Tip/Ring on the TPU 15A.

If you call them, they're usually pretty good with their technical support.

The hardest part was finding an old punch tool - I believe it's a type 66.