532 BELL SYSTEM TECHNICAL JOURNAL 



Example 

 As an example of the general procedure in specifying satisfactory 

 net losses for terminal circuits, consider a 500-mile 19-gauge H-44-25 

 four-wire cable circuit not equipped with echo suppressors. From 

 the information in the paper by A. B. Clark and H. S. Osborne referred 

 to above: 



1. The minimum echo net loss is about 4.5 db. 



2. The transmission variations are about ± 2 db. 



3. Therefore, the minimum working echo net loss is about 6.5 db. 



4. The minimum working crosstalk net loss is about 6.6 db. 



5. The minimum working singing net loss is about db. 



6. Therefore, the minimum working net loss of the circuit is about 

 6.6 db. 



It will, therefore, be satisfactory to specify 6.6 db with normal 

 variations of zt 2.0 db for the circuit in question. 



