622 



THE BELL SYSTEM TECHNICAL JOURNAL, JULY 1951 



K EQUIPMENT 

 ujZ NUMBER 



HO 



'ERM, 



INTERMEDIATE 

 ^^"'SWITCH , STAGES~ 



'X >i 



SLEEVE 



TRUNK 

 CIRCUIT 



termination and 

 coding element 

 (one per number) 



— 9 — 9 — 9 — 9 

 THOU HUNDS TENS UNITS 



(a) 



40 CODE — >. 

 MARKING LEADS 

 BUS BAR SYSTEM 



O 



z 

 Ox: 



COMMON 

 EQUIPMENT 



IDENTIFICATION 



START TONE 

 C— - LEAD 



Q-uj 



S? 



t- EQUIPMENT 



03 



HO 



UJ 



INTERMEDIATE 



Ox: 

 O 



TU 



---J 3 

 O 



OSCILLATORS AMPLIFIERS 



0. 

 0- 



(c) 



THROUGH 

 CONNECTING— >*->; 

 RELAYS 



Fig. 13 — Identifiers with various arrangements of coding elements. 



COMMON 

 RECEIVER 



