You probably want to start with PySerial: http://pyserial.sourceforge.net/
But, the details really depend on the application.. what are you talking to at the other end? Do you need a general terminal program? You can probably find xmodem and zmodem libraries, but if you control both ends, rolling your own would be easy enough, just be sure to check for data corruption. Zmodem is preferred, since Xmodem can pad the end of the file with NULLs. If you are working through a modem, you will need to be familiar with the Hayes AT Command Set. Google is your friend. Answering incoming calls is harder, you need access to the modem control lines (or you can tell the modem to answer manually). This is a platform specific problem. You might start out with a null modem cable between two computers (or even the same computer, with two serial ports), just to get familiar with the system. Cheers _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor