Skip Thanks for the reply. I got it working now by doing some reverse engineering. I found the basic application notes were okay except for the COR line. It was the cause of my problem with the Pyramid transmitter being key up all the time. I moved it to the Channel indicator on the radio side Pin 21 and bingo it came up started working just fine. What pin on RX/TX did you use for the COR line to make it work? Mike
