Hi, I recently built a RS-232 interface for my Yaesu. I used a circuit from the '98 ARRL Handbook - its not much more than 3 IC's - a MAX232 level converter, a 7417 TTL buffer, and a 7805 5V regulator. Check a recent copy of the ARRL handbook or maybe you can find the Feb '93 QST article "Everything you wanted to know about computer-controlling your radio". (its available for free download from the ARRL website if you're a member.) GL, Chris.