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BELL SYSTEM TECHNICAL JOURNAL 



indicate whether the message printed originated with the New York or 

 with the London operator. Messages transmitted from the local 

 machine are typed in red while those received from the distant term- 

 inal are typed in black. This was accomplished by modifying the 

 mechanism of the machine to automatically shift a half red and half 

 black typing ribbon. 



Fig. 2 — Transatlantic telephone operator's position showing arrangement 

 of printing telegraph equipment. 



The voice-frequency telegraph terminal equipment' and its asso- 

 ciated apparatus are shown in Fig. 3. The equipment comprises the 

 voice-frequency terminal set for repeating between the local d-c printer 

 loop circuit and the a-c line circuit. The printer switching circuits, 

 testing arrangements, and monitoring equipment are, for convenience, 

 included in the same assembly of apparatus. The installation includes 

 all the equipment necessary for one channel of a two-tone carrier tele- 



