Thanks to all who provided assistance. Problem solved, it was indeed a
"break" signal (base address + 3, bit 6) that I needed to send to toggle the
switch.

Craig Webb

At 12:31 PM 3/11/98 +0000, you wrote:
>> >Does anyone know off-hand the memory address and value for setting the RS232
>> >TX line high on a PC? I need to trigger a relay connected to this line.