Abstract: A transponder for use with a pair of dual-controllable systems remote from each other, such as a two-player computer operated game, allows the players and their associate game units to interactively play against each other from remote locations.The transponder receives status words from an associated controller, retains a copy in temporary storage, and formulates command words for a similarly configured transponder associated with the remote unit. The command word includes a status portion comprising a replica of the stored word, an error detection code, and a confirmation code. The error detection code is used to detect transmission errors in received words, and the confirmation code is used to indicate error-free reception of words from the remote unit. A command word is sent responsively to receipt of each received command word.