Abstract: An intra-train communication system includes a locomotive control unit (LCU) establishes a communications link between a lead unit and a remote unit which operate using different protocols and/or in different frequency bands. To accomplish this objective, the LCU automatically detects the type of lead unit and remote unit installed on the train. If the types are not the same, the LCU resolves any serial link protocol and arming differences that might exist in a manner virtually transparent to train operators. As a result, data is communicated between the lead and remote units in a way which requires less operator intervention and no software changes to the control computer of the head unit.