An electromechanical data storage arrangement is interfaced with a host. The interface may include a conductor that carries read and write gate signals. Another conductor carries both a servo sync mark and an error signal. The storage arrangement includes an external serial interface connected to a host serial interface applying a device identification to a portion of serial control-related data that travels over the interface. A serial router in the storage arrangement uses the device identification to manage the control-related data between the interface and a number of serial devices and associated interfaces within the storage arrangement. The serial router is in selective data communication with each of the device serial interfaces, for using the device identification to direct a host-asserted command to a targeted device where each device is controlled by a different command set such that the system can be customized for different command sets of different devices.