Com Port and Resistance

My client has a device that he wants to monitor. It has 3 buttons on it and, according to him, when each button is pressed, it lowers the resistance on a specific pin. I have the device connected to my Com 1 input, but I see nothing there using MsComm Control (using the .Input property). The port opens ok, but nothing is there. Anybody out there with a plan??

Thanks,
Jeff

Assuming I understand what you're doing -

The RS232 specification senses voltage changes, not resistance changes. You will have to install some kind of intermediate device that detects delta Ohms, and sends a signal to the COM port. There a lots of digital VOM's out there, some of which offer continous output signals of different types.

Start with a local Radio Shack if you're in the US.