5.4 | Connecting COMMAND to the ISOBUS ECU Mounted In-cab With the COMMAND ECU mounted in-cab: Locate the in-cab 4-way ISOBUS connector. Connect the 4-way ISOBUS connection on theĀ  T3H-C006 cab breakout to the connector. Use an additional adapter if connecting to 9-way cab ISO receptacle. ECU Mounted at Rear of Tractor With the COMMAND ECU mounted at the rear panel or near the ISOBUS breakaway plug: Disconnect the existing 4-way plug from the ISOBUS implement breakaway connector. Connect the disconnected plug to the receptacle on the ISOBUS "T" connection on the T3H-C005 external breakout. Connect the 4-way ISOBUS "T" plug into the ISOBUS implement breakaway connector.