Pentaconta A1 switching system

Making effective use of the well-established Pentaconta switching equipment and techniques, the A1 system has been developed to fit in the public telephone network of North America. The vertical selector of the standard Pentaconta crossbar twitch when used as a line unit is divided into 3 parts, the top is for trunks, the middle section for lines, and the lower part is a junctor section. Connections between some vertical bar and for a wider range of lines and-trunks through the operation of 2 vertical bars over the junctor sections of two switches. The link switches for connecting junctors to lines are divided into 2 vertical sections (lines) and into 4 horizontal sections junctors Each switch can handle 192 junctors from 6 line units. After a small trial installation to prove the system, a computer program of exact simulation based on the complete system logic was run to determine traffic capacity. Printouts were provided on the number of calls completed, types of connections made, average use of elements, and much similar data. Computer calculations were based on generated traffic that was collectively and individually random in time of origination and exponential in holding time about a mean of 120 seconds. The early part of each computer run was discarded as a transient preceding the steady-state conditions. A second large installation in Las Vegas, Nevada, was based on this extensive analysis and its performing satisfactorily in all respects.