E-type telephone repeaters

THE INSERTION of repeaters into telephone lines to make up for circuit losses is a very common practice today. The use of negative impedance to overcome transmission loss is an old idea but only recently used to any great extent in the exchange area plant. A series type of negative impedance repeater, called the E1 telephone repeater, has found favor in the Bell System and its use has stimulated a demand for still more economical designs including a companion shunt type of negative impedance repeater. Through the use of these new E-type repeaters, it is possible to reduce the attenuation and improve the return loss of voice-frequency lines so that exchange area trunks can be used as links in a toll connection.