APPLYING CARRIER TELEPHONE SYSTEMS 587 



carrier message circuits between the system terminals. This is not 

 necessarily typical of what the usage of type K channels will be, but is 

 brought about by their relatively limited application to date and 

 demonstrates the flexibility of the type K carrier circuit in fitting in 

 with the other types of circuit facilities. 



Conclusions* 



Although experience with type K systems in service is rather limited, 

 they are providing circuits of excellent quality and performance. The 

 band width of the individual channels slightly exceeds the original 

 estimates. Such instabilities of transmission as have been experienced 

 have, in most cases, been corrected before service was interrupted and 

 have been caused largely by non-recurring troubles inherent to most 

 installations of new equipment. In brief, the operating experience 

 with type K cable carrier systems confirms the view that they are 

 expected to become an important means of providing additional long 

 distance telephone circuits over cable facilities. 



References 



1. C. W. Green and E. I. Green, "A Carrier Telephone System for Toll Cables," 



Bell System Technical Journal, Vol. 17, No. 1, January, 1938. 



2. M. A. Weaver, R. S. Tucker and P. S. Darnell, "Crosstalk and Noise Features 



of Cable Carrier Telephone System," Bell System Technical Journal, Vol. 17, 

 No. 1, January, 1938. 



3. R. W. Chesnut, L. M. Ilgenfritz and A. Kenner, "Cable Carrier Telephone Ter- 



minals," Bell System Technical Journal, Vol. 17, No. 1, January, 1938. 



4. A. J. Aikens, "Suppressing Noise and Crosstalk on the Type K Carrier System," 



Bell Laboratories Record, Vol. 17, No. 7, March, 1939. 



5. F. W. Amberg, "Crosstalk Poling for Cable Carrier System," Bell Laboratories 



Record, Vol. 17, No. 6, February, 1939. 



6. P. W. Rounds, "A Longitudinal Noise Filter for the Type K Carrier System," 



Bell Laboratories Record, Vol. 17, No. 9, May, 1939. 



7. H. H. Spencer, "Power Plant for Broadband Repeater Stations," Bell Labora- 



tories Record, Vol. 17, No. 8, April, 1939. 



8. L. Hochgraf, "Crosstalk Balancing for the Type K Carrier System," Bell Labora- 



tories Record, Vol. 17, No. 6, February, 1939. 



