An apparatus (20) such as a television signal receiver controls an external device (40) such as a digital recording/reproduction device via a digital data bus (30) by remapping keys on a user input device (10). According to an exemplary embodiment, the apparatus includes an input/output terminal (13) operative to enable signal transfer between the television signal receiver (20) and an external device (40) via a digital data bus (30). A processor (14) is operative to detect a first command signal of a first control protocol from a user input device (10), and to detect one of first and second modes of the television signal receiver (20). The processor (14) detects the first mode in response to making a connection between the television signal receiver (20) and the external device (40) via the digital data bus (30), and detects the second mode in response to terminating the connection between the television signal receiver (20) and the external device (40) via the digital data bus (30). The processor (14) enables the input/output terminal (13) to output a second command signal of a second control protocol to the external device (40) via the digital data bus (30) responsive to the first command signal if the first mode is detected. The processor (14) enables a function of the television signal receiver (20) responsive to the first command signal without enabling output of the second command signal to the external device (40) if the second mode is detected.