Device Identification by Test Signal Duration
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
In the design of a universal attachment card to handle the interfacing of a variety of external devices to a data-processing unit, selection of the appropriate operating code requires an identification of the type of device that is actually attached. A classical approach to this problem is to define a unique cable connector pin (which is usually grounded) to represent each device type. If a large number of attaching devices are anticipated, then an equally large number of connector pins must be uniquely assigned and dedicated.