EQUALIZING AND MAIN STATION REPEATERS

The equalizing and main station repeaters, together with the L‐4 control center and command looping circuits, provide for the equalization and remote fault location in the L‐4 system. The use of pre‐ and postequalization procedures requires virtually identical circuits at the sending and receiving main station repeaters, while abbreviated versions of the same equipment are placed in up to two line equalizing repeaters per main section. In most cases these equalizing stations occur at approximately every twenty‐fifth repeater in a completed system. The fault‐locating circuits are distributed over the entire system and the control circuits required for their activation are located at the equalizing points. © 1969 The Bell System Technical Journal