TOLL TRANSMISSION IN THE UNITED STATES 143 



of additional channels be simplified by the availability of these new 

 systems, but the cost per channel should be somewhat decreased. At 

 the same time the quality of the circuits, from the standpoint of 

 voice transmission, has been improved, so that a multiple gain is 

 obtained. 



Lecturer's Note: The lecturer wishes to acknowledge his indebtedness to a 

 number of members of Bell Telephone Laboratories' staff. In particular, 

 he wishes to thank Messrs. H. A. Affel, A. B. Clark and P. C. Jones for their 

 assistance in preparing this material. 



