Thanks, Bert. The Multi-Code 1090 receiver (dooropenersandmore.com/manuals/109020.pdf) I'm considering is actually labeled as 1 - 24v (white wire), 2 - Relay (black wire) and 3 - Common (red wire), with the doorbell going to 1 and 2.
My Touch N Go has the doorbell going to 2 and 3, so I'm...