Icom CT-17 Signal Detection Modifcation

If you're using some of the latest software available or want to control your Icom radio with your computer, you might find this information helpful. Here's how to modify your Icom CT-17, or similar computer interface to make it support signal detection.Signal Detection works by attaching a cable to the Recorder Remote jack on the radio and to the RS-232 (Com. Port). This additional cable makes it possible for the software to detect when there is a signal present on the radio, so that the software can stop scanning, searching, or log a hit.The cable needs a 1/8" mini plug for the radio side. The other end needs to be connected to the RS-232. One wire needs to be connected to pin 20 (Data Terminal Ready), and the second wire needs to be connected to pin 22 (Ring) or to Pin 8 (Carrier Detect). Make sure you choose the proper signal detection method in the Radio Setup Dialog Box. That's all! I haven't seen a CT-17, but I know others have performed this enhancement. I have added it to a homemade interface, see below, and an interface that I ordered from J-COM Enterprises. Both modifications were pretty easy to perform, especially considering I had not used a soldering iron before building the homemade interface.If you don't have an interface yet here's information on an inexpensive homemade alternative to the Icom CT-17. I spent about $25 on parts and a few hours building it. Nigel Thompson KG7SG wrote the article, "A Low-cost PC Interface for Icom Radios" in QST July 1992 Page 37 describing the parts and how they go together. I've added the signal detection enhancement above to this one and it works great. The interface draws its power from the RS-232, so no external power supply is needed. The following picture was provided by Ron Harris, who has made the modification to his CT-17.DISCLAIMER:I AM NOT AN ELECTRICAL ENGINEER, BUT AS FAR AS I KNOW THIS MODIFICATIONSHOULD CAUSE NO HARM. MODIFY AT YOUR OWN RISK.