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BELL SYSTEM TECHNICAL JOURNAL 



signals for transmission through the switchboard. The trunk is then 

 carried to the teletypewriter test board where a termination is provided 

 for the purpose of testing the equipment. From the test board the 

 trunk is cabled through the relay equipment to the distributing frame, 

 where it is cross-connected to the switchboard multiple, the multiple 

 for all three lines of switchboard being doubled up at the distributing 



ANSWERING AND COMPLETING 

 MULTIPLE TO 1799 



COMPLETING MULTIPLE 

 1800 TO 3599 



ANSWERING AND COMPLETING 

 MULTIPLE 1800 TO 3599 



FROM MAIN 



DISTRIBUTING 



FRAME 



Fig. 4 — Diagram of cabling for subscriber lines on No. 1 Teletypewriter Switchboard. 



frame terminal strips. Ordinarily, with the inverted subscriber 

 multiple arrangement, there will be a capacity for 480 inter-toll trunks 

 equipped with answering lamps in the first two lines of switchboard. 

 However, opportunity is provided for increasing this capacity by the 

 provision of the separate inward and through switchboard. As 

 described above, the lamps in this inward board may be omitted from 



