Thanks to everyone who helped me solve this problem. The trick is to use a serial cable that has pin 2 -> pin 2 and pin 3 -> pin 3. DO NOT use a cable with the connections to pins 2 & 3 crossed - as is shown in the TenTec manual! Right now I'm using a cable with just three wires that connect pins 2, 3, and 7, and everything seems to be working just fine. 73 es Best Wishes for the Holidays!! - John, W4AU --