VHF was not operating properly. It was not possible to ebter an actice frequency as the flip-flop button was not doing anything. The unit was displaying STUC which means the mic has been open for 30 seconds or more.
Ian found the problem to be with the terminations in the intercom. Also, the passengers' jacks were not wired correctly.
Unit operating successfully from both sets of jacks. Testedthe transmissions with a hand held radio - OK.
