Being somewhat lousy rc-helicopter pilot, I decided to invest to HeliCommand 3a stabilization unit. Unit itself is easy to install but it quickly became clear that pc-interface is almost necessary to operate the unit properly.
I did not want to order the cable separately since the cable is somewhat expensive and can be constructed for few euros. I hacked this circuit together by using some schematic I found from the web and the pictures about the cable pcb as a reference. Interface can easily be constructed on stripboard from easily available components.
The numbers on the leads are numbers for 9-pin D-female connector. Connector to HeliCommand is standard 3-pin female servo plug, where middle connector is not used. When connecting cable to HeliCommand, white wire goes towards the center of the unit. Note that on the pcb image two red squares mark the spots, where the copper strip needs to be cut. Remember to cut traces also under the resistors.
I glued the pcb inside some plastic box which I had laying around and it seems to work fine with the HeliCommand software.