AVv 



If-^^A^lAAAr 



GROUND ! 



TRANSMITTING OR 

 RECEIVING LOW-GROUP UNIT 



KEYER 

 TRANSFORMER 



^A/v — KH 



^ ' TO KEYERS 3700^^ i 

 I S OF OTHER — *- , — 

 L-^ CHANNELS _L ' 



^A^ — w- 



+130 





(b) 



Vv\--AVV-5f 



'M" 

 LEAD 



'^E'^LEAO 

 TO SWITCHBOARD 



+130 V 



BAND- PASS 



AMPLI- /^'"^JM 

 FIER (3700^) 



-40V 

 BIAS CHANGER 



Fig. 6(a) — 3700 cycle signaling tone oscillator circuit, 

 (b) — Channel signaling keyer circuit, 

 (c) — Channel signaling receiver circuit. 

 15 



