Abstract: A switch for selecting, from among a plurality of devices, a device to be coupled to a data line, such as an ISDN line. The switch includes a data line receiver coupled to a data line interrogator and switch controller. The switch further includes a device identifier coupled to both the data line receiver and the data line interrogator and switch controller, and a plurality of buffers which can be enabled by the device identifier, thus coupling a device, connected to one of such buffers, with the data line, also connected to such buffers. Information received by the data line receiver is passed to the data line interrogator and switch controller for evaluation to determine whether such information is device identification information.