Adapter for synthetic or redundant remote terminals on single 1553 bus

A remote terminal adapter device is disclosed. The adapter device includes control processors in communication with a bus controller via a dual redundant data bus (e.g., MIL-STD-1553) having primary and secondary data buses or channels. The adapter device includes analog relays connecting the primary and secondary buses to a main remote terminal (RT) device configured for control of an aircraft subsystem. Additional analog relays connect the data bus to one or more auxiliary or additional RTs (e.g., configured to backup the main RT or simulate the controlled subsystem and its responses. The adapter device may monitor the data bus for traffic and allow the redundant RT to access the data bus (from the same remote terminal) address as the main RT by activating and deactivating the analog relays.