AUTOMATIC PRINTING EQUIPMENT 421 



mitter on each section so that one or more channels on both cable 

 sections may be terminated at the repeater station without interfering 

 with automatic repetition of traffic on the remaining channels. 



Not only is it possible to link two or more simplex cable sections 

 together through automatic repeaters, but it is also possible to link 

 such a system through repeaters with a duplexed land line multiplex 

 without introducing serious complications. The printer on the re- 

 reiving side of each channel of both the land and cable circuits at the 

 repeater station may be replaced with an automatic reperforator which 

 will prepare from the incoming signals a perforated tape for retrans- 

 mission. As this tape leaves the reperforator it is automatically 

 drawn through a standard transmitter which will transmit the signals 

 into the corresponding channel of the next section of line or cable. 

 In moving between the reperforator and transmitter the tape passes 

 under a contact closing lever arranged to stop the operation of the 

 transmitter when the slack in the retransmitting tape drops below a 

 predetermined minimum as the result of a difference in transmission 

 speed on the two sections or the stoppage of the reperforator on the 

 simplex section during the transmitting periods. This avoids the 

 possibility of mutilation of the transmitted signals or tearing the tape. 



The provision of a comparatively large number of traffic channels 

 and automatic repeaters by means of which traffic on any or all 

 channels may be automatically repeated into the other cable sections 

 or land telegraph lines affords a high degree of flexibility in handling 

 and routing traffic and permits the several channels to be terminated 

 at the two ends in widely separated points. 



Conclusion 

 Although the general principles of the system and the general 

 design of the apparatus described herein are applicable to all loaded 

 cables irrespective of length or construction, it is quite obvious that 

 the detailed design of the various pieces of apparatus required will be 

 determined to a great extent by the electrical characteristics of the 

 particular cable to which they are to be applied and by the operating 

 and traffic requirements which that system must fulfill. Equipment 

 of this type can not therefore be standardized to the degree possible 

 in the case of similar equipment for land line service, and the provision 

 of apparatus for each cable becomes a special engineering problem 

 which must be worked out with the cooperation of the engineers of 

 the operating company in order to make the apparatus capable of 

 satisfactorily meeting all of the conditions which will obtain in subse- 

 quent commercial use. 



