Marshall,

Try the following in your SendFrame routine.

void SendFrame()
{
char i;

while (OKtoSend == BusBusy)
{
VariableDelay(TL0);
}

ModuleStatus = ACTIVE;
RS485State = TX; //Enable the RS485 Driver

//............................


//before sending first byte of the string

DELAY(for time to send 1 byte);
TI=1;

//............................


SendByte(frame.SystemAddress);
//.........................etc
}

Hope it helps to recognize a bug.

Regards,
George