An adapter for coupling a vehicle communication interface device and a computer processing device to a signal source comprises a first port configured for communication with the communication interface device and a second port configured for communication with the computer processing device. The adapter can include a receptacle configured to receive signals having a data portion and a power portion. The adapter can further identify the received signals as being one of vehicle signals or computer signals. Moreover, the adapter can include a relay having a first state associated with the vehicle signals for relaying the vehicle signals between the first port and the signal source and a second state associated with the computer signals for relaying the computer signals between the second port and the signal source. The relay can be selectively placed in one of the first and the second states associated with the received signals as identified by the receptacle.