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BELL SYSTEM TECHNICAL JOURNAL 



calculations. Investigation of the combinations poorer than 74.5 db 

 indicated that most of the pairs involved could be assigned either to 

 non-repeatered short circuits or to repeatered short circuits on which 

 the repeater gains were considerably lower, with consequent lower 

 crosstalk gains, than on the full length circuits assumed for the limit 

 of 74.5 db crosstalk. This required the opening of one splice near 

 Toronto for pair rearrangement. 



It was decided to place the cable under permanent gas pressure in 

 order to control service interruption as far as practicable. As there 

 was no previous experience available for cables of this size, an investiga- 



400 800 1200 1600 2000 2400 2800 3200 

 frequency in CYCLES PER SECOND 



Fig. 13 — Return loss — frequency characteristics; measured from Toronto to Barrie 

 on 87 pairs; building-out condenser adjusted to theoretical value. 



tion on the job was undertaken to obtain the information necessary for 

 successful application of the gas pressure installation. Based on the 

 results obtained, the installation of gas pressure was completed 

 satisfactorily. 



Acknowledgment 



The design and installation of this cable represent the coordinated 

 efforts of many people — members of the organizations of the Bell 

 Telephone Laboratories Inc., the American Telephone & Telegraph 

 Company, Northern Electric Company, Western Electric Company 

 and the Bell Telephone Company of Canada — too many for anyone 

 to be specifically mentioned. To all of these credit is due and is here 

 given. 



