Hi,

>
What signal would I have to send and which two wires would I need to tap into, on a standard 9 pin com port?
>

Top of my head - you can set either DTR or RTS high to generate a 5v output. On a 9-pin I think DTR is pin 9, RTS is pin 4 (but better check that).

FWIW if you also need inputs you can apply 5v in to CTS(pin5) or DSR(pin6) and maybe DCD(pin1)?

HTH,
Viv