You should start a new thread rather than bumping a post as old as this one. SC4000 has master/slave GE Gen II SX units, use the GE LX EV100 handset with the Gen II SX cable, all available from Flight Systems. Handset part number 41-LXHS-00, cable is 41-1002-01
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.