connect simple button through rs-232

Since you have only one button, I'd connect it across an output like DTR on pin

4 and input like DSR on pin 6. It won't swing +v to -v but as it should but many devices, especially laptops, don't adhere to the standard.

The status register will be what you read for the button push.

Connector pin assignments

Specific instructions from a similar box + software to ease the task

com1 is at 3F8, its status register is + 4 ports from there or 3FC...Windows generally make direct port manipulations difficult.

Another good place to visit is Jan Axelson's page, I'd recommend you buy her book.

I've done something similar making a simple rotation counter. I connected the RTS to a 10k resistor, then to the switch, and then to then Rx pin. When ever the switch made contact, jibberish was put in the serial port input buffer. My program checked the input buffer on a periodic basis to see if anything was in the buffer. If there was anything in the buffer, the switch had made conact. If the buffer was empty, then no switch action.

hello so it worked for me when i connected 4 and 2 pins together. you can see details of the progress here:

thanks a lot, jim