George Heys - Cambridge OH
Rex A. Aleshire - Cambridge OH
Frank Hines - Cambridge OH
William M. Belknap - Cambridge OH
NCR Corporation - Dayton OH
A system is disclosed for selectively serially coupling a plurality of stations in a communications network into a single communications path. In the system of the invention, a plurality of tap boxes are serially coupled into the single communications path. Each station is coupled to a desired associated one of the tap boxes by way of an associated tap cable. When the tap cable is connected to a first portion of the tap box, a first impedance corresponding to the characteristic impedance of the single communications path is serially coupled into the single communications path to enable the station associated with the tap cable to be coupled to the single communications path by way of the first impedance. When the tap cable is connected to a second portion of the tap box, the first impedance is effectively removed from the single communications path and a test impedance is coupled to the tap cable to enable the station associated with the tap cable to test itself. In a first embodiment, the first and second portions of the tap box are respectively the tip and ring contacts of a stereo jack.