IN-BAND SlXCiLE-FREQUENCY SIGNALING 



1325 



The operation of the receiver will be explained by describing its action 

 (except for pulsing which will be described later) when signal frequency 

 is received. This ac tone is amplified (or limited if it is too large) and 

 then passed on to the signal and guard networks where a relatively 

 liigh voltage results in the signaling channel and a lower voltage in the 



j -40 V "=" 



Fig. 11 — Simplified diagram of 2,600-cycle signaling circuit. 



