As I found out, if you are interfacing to a PC, you do not need to use anything as fancy as a MAX232. In fact, a plain old 74HCT00 (quad nand gate) will suffice. Simply take PC output connect it to a 22k resistor and tie it to the inputs of one of those gates. The output of that gate will be the RS232 input into your device.
Similarly, take the output of your device, tie it to the inputs of another gate and that output will be the input into the PC.
This is not fully RS232 compliant but it's awfully cheap and works wonders with PCs.
in reply to Re: Kludging the serial port
in thread Kludging the serial port