Abstract: In a communications system having components which are interconnected via communications links, the system is provided with capability of responding to the application of a predetermined test signal to a link with information which identifies that link. Such information can take a variety of forms including the name of one or more persons assigned to use the link, and/or the telephone number or numbers associated with the link. This capability greatly reduces the time and expense associated with the maintenance and testing of a variety of communications systems, such as PBXs and central office switching machines.