How do I get serial port to work with my HAM RADIO hardware?

Hello....My computer has a serial port that I used for a HAM RADIO application. The hardware item is a "TNC" which is similar to a modem but connects to the serial port and radio and sends signals out over the air. I have a mailbox in the TNC and can connect to others with similar setups. My problem is first of all to get a HAM RADIO PACKET program to work under LINUX. Then figure out getting the TNC to talk to computer under linux. Are there any other HAM radio people in KNOPPIX LAND that can help me????? Thanks...bob58 :lol: