A new crossbar link design for step-by-step common control

In order to apply common control features in Bell System step-by-step (SXS) offices, an interconnecting link is necessary between the line finders and the common control equipment. The features of a new crossbar link designed for this purpose are described, and the following technical and economic considerations are discussed: traffic-handling capacity, minimization of control circuitry, emergency control transfer, controlled access to Touch-Tone or rotary dial registers, and flexibility of equipment for use in various office sizes.