The 2A Line Concentrator

The 2A Line Concentrator is a high-speed, medium range system designed for use in the No. 5 crossbar system to provide range extension with more rapid connection of lines than is now possible. An ac signaling technique and solid-state logic circuits are combined with relay and crossbar switching circuits to provide a concentrator system with a range of about one thousand miles and a call setup time of approximately 175 milliseconds. These are improvements over the existing 1A Line Concentrator 1 (LC1A) system which is range limited to about twenty-five miles and the 1A Line Concentrator system modified for extended range with a call setup time of about 1.8 seconds.