REMOTE CONTROLLED LINE CONCENTRATOR 



261 



cuit connection between printed wiring plates is through pins which ap- 

 pear in the recess and to which the smaller plate is soldered. 



6. BASIC CIRCUITS 



a. Diode Gates 



All high speed signaling is on a pulse basis. Each pulse is positive and 

 approximately 15 volts in amplitude. There is one basic type of diode 

 gate circuit used in this equipment. By using the two resistors, one con- 

 denser and one silicon alloy junction diode in the gate configuration 

 shown in Fig. 8, the equivalents of opened or closed contacts in relay 

 circuits are obtained. These configurations are known respectively as 

 enabling and inhibiting gates and are shown with their relay equivalents 

 ill Figs. 8(a) and 8(b). 



In the enabling gate the diode is normally back biased by more than 

 the pulse voltage. Therefore pulses are not transmitted. To enable or 



INPUT 



ENABLING GATE CIRCUIT 

 CI 



OUTPUT 



(a) 



ENABLING GATE SYMBOL 



INPUT 



OUTPUT 



CONTROL 



EQUIVALENT RELAY CIRCUIT 

 OUTP UT 

 INPUT f 



CONTROL 



CHli^ 



INPUT 



INHIBITING GATE CIRCUIT 

 Cl 



OUTPUT 



INHIBITING GATE SYMBOL 



INPUT 



OUTPUT 



CONTROL 



EQUIVALENT RELAY CIRCUIT 

 OUTPUT 



DhUHl 



Fig. 8 — Gates and relay equivalents. 



