Batboard

Hello I need help with a CDM 1250 and using a TPL Mobile amp with the bypass relay. How do I controll the bypass relay from the radio. I would assume it is from the 20 pin connector on the back but what pin and what do i program the pin to?

You can switch the amp into TX/RX with an IRF511 power Mosfet.
The device is a TO-220 case, three terminal.

Simple bypassing, and a good diode across the relay terminals for inductive kickbak(1N4007).
You will have to address the RF side due to power input requirements, such as chokes, resistors for current limiting.

Heck, you can do this on the cheap with a 2N2222A and a few parts in the junk box!
You simply have to rectify the RF and convert it to D.C, then limit the amount of signal into the base of the transistor.