Reply to "Weak or NO DCS signal from TIU"

The only time I get a signal reading on the scope of any type, is when I first power up the TIU.  When I use the handheld tethered or wireless, I don't see any output signal response on the scope for any of the channels, not transmitting at all.  That's why I thought the problem might be a faulty MAX4693 receiver chip which was not receiving commands from the handheld, so the TIU would not transmit anything out and not execute internal commands to the TIU.    Is there a way to trace the signal in the TIU or does anyone have a schematic of the TIU.  Any suggestions?

Thanks

Bob D