528 BELL SYSTEM TECHNICAL JOURNAL 



3. The New York operator connects to an idle trunk in the New York-Chicago mul- 

 tiple: Plugs the completing end of the cord into the trunk jack and operates the cord 

 ringing kev for 2 seconds. The trunk multiple lamps at Chicago light. 



4. A Chicago operator answers: Plugs the answering end of a cord into the trunk 

 jack with the cord typing key operated. The trunk lamps are extinguished. The 

 Chicago operator communicates with the New York operator. ^ 



.'>. The Chicago operator completes to an idle trunk in the Chicago-San Francisco 

 multiple: Plugs the completing end of the cord into an idle trunk jack and operates 

 the cord ringing key for 2 seconds. Releases typing key. The trunk multiple lamps 

 at San F'rancisco light. 



6. A San Francisco operator answers: Plugs the answering end of a cord into an 

 idle trunk jack with the cord typing key operated. The trunk lamps are extinguished. 

 The San Francisco operator communicates with the New York operator. 



7. The San Francisco operator completes the connection to the called subscriber line: 

 After making a tip busy test with completing cord to insure that the called station is 

 idle the San Francisco operator plugs into the jack and operates the ringing key in 

 that cord. The ringer in the San Francisco station is operated. 



8. The called subscriber answers: The answer is received on the operators' tele- 

 typewriters at the San Francisco and New York switchboards and at the New York 

 subscriber station. The San Francisco and New York operators release the cord 

 typing keys leaving the communication between the subscribers. The New York 

 operator starts timing the ticket. 



9. The calling and called subscribers disconnect: Lamps A and F light. The New 

 York operator completes the timing of the ticket. 



10. The outward {New York) operator sends the discojinect signal: Operates cord 

 key momentarily and pulls down both cords. After 10 seconds lamps C, D, and E 

 light. 



11. The inward {San Francisco) and through {Chicago) operators disconnect: 

 Upon noting the disconnect lamp signals both operators pull down both cords. 



If during the progress of the call the subscriber desires to regain 

 the attention of the operator, a recall signal is sent. The procedure 

 in this case is as follows: 



12. The calling {or called) subscriber recalls: Operates power switch at the station. 

 Cord lamp A (or F) flashes. 



13. The operator answers the recall: Operates cord typing key connecting her tele- 

 typewriter to the circuit. The flashing cord lamp is extinguished. 



14. The outward {New York) operator recalls the inward and through operator at 

 Chicago: Operates recall key in cord. After 7 seconds lamps B, C, D, and E flash. 

 The outward operator releases the typing key momentarily to extinguish the lamp. 



15. The inward a?td through {San Francisco and Chicago) operators challenge: 

 Operate cord typing keys which extinguish the flashing lamps, and then challenge by 

 typing. 



Conclusion 



This paper has outlined the technique of teletypewriter switchboard 

 operation as it stands today. Although the designs as here outlined 

 have given satisfactory service within due limits of economy, the 

 expansion of the system and experience in its operation will un- 

 doubtedly lead to changes in the design of both the equipment and 

 circuits and to changes in the methods of operation to increase the 

 efficiency and improve the quality of the service. 



