pl more space is required, attach additional sheets. Identity with aircraft nationality and registration mark and date work completed.) Installed a GTE/Magnavox C-2000 Digital Airborne Telephone System consisting of: 1 Ea. Air Radio Telecommunications Unit (ARTU), P/N 724855-801 1 Ea. ARTU Rack, P/N 724868-802 1 Ea. Duplexer, P/N 620317-1 3 Ea.