The GDC25 Data Combiner reads in all ARINC 429 labels from a Trimble TA-12 GPS Receiver then retransmits all labels as received except labels 162, 163, 343, 344, 346, 347 and 371. Labels 140, 141 and 377 are generated and label 133 is derived from incoming data, formatted in a proprietary ARINC 429 format, then transmitted along with the received data to a Litton LTN-92 Inertial Navigation System.