What was found
ON TAXI IN, CREW EXPERIENCED A LOUD CONTINUOUS SQUEAL IN THEIR HEADSETS AND ALSO OVER THE COCKPIT SPEAKERS. COMMUNICATION WAS IMPOSSIBLE WITH THE TOWER. OUR CUSTOMER SERVICE REP HAD US DISCONNECT THE HEADPHONE/MIC JACK ASSEMBLY IN THE AFT EQUIPMENT BAY. THE SQUEAL WENT AWAY. A NEW UNIT WAS ORDERED AND INSTALLED. A NEW UNIT WAS ORDERED AND INSTALLED. THE SYSTEM IS ONLY ACTIVE WITH WEIGHT ON WHEELS , BUT IT COULD STILL POSE A SERIOUS COMMUNICATION PROBLEM ON THE GROUND AT A BUSY AIRPORT.