Change from for TMCC to Legacy Control System

You'll have to add a PowerMaster Bridge for the PowerMaster or replace it with another TPC.  The MTH compatibility doesn't change with Legacy.

gunrunnerjohn, thanks for the reply. Would I still be using the command base that I have for my present TMCC CAB1 System? And would I be using the keys on the CAB2 remote with a TPC 300 or 400 to access the features on Protosound 2 engines like I do with the CAB1 remote?

You'd be using strictly the Legacy controller.  You can daisy-chain the old command base and use it with the Legacy command base, but that's not necessary.  If you use the old command base, the PowerMaster Bridge is not in the mix, they use the same frequencies as the old command base.