

.?(..' mil. I. sysTiiM I liciix/c.ii. .uHky.ii. 



ment. Different dertotiioiis of the xoliineler needle will, of course, 

 be obtained depending on whether the loop tested is a single party, 

 two-party or tV)ur-part\ line and also on whether 1 m f "r 2 ^ f- con- 

 densers are provided in the substation sets. These oin(iitinii> nui>t 

 l)e known by the testnian if he is to properly interpret liie testini; 

 results and detect missing or defecti\e condensers. 



Standard Types of Testboards. Pictures of two of the latest tyi)es of 

 toll and local testboards are shown in Figs. 8 and 9.] These boards 

 provide circuit arrangements for making most of the direct current 



tests which have just been described and also some of the alternating 

 current tests described below. The wiring of the test cirruits to keys, 

 jacks and plugs and the provisions made for picking u]) \arious tele- 

 phone circuits for test greatly facilitate routine maintenance work 

 and the location of troubles which occur in service. Modifications 

 and various arrangements of the tests described above have been 

 provided for in these boards to meet different operating condilion- 

 which may arise. 



The test board shown in Fig. 8 is designed iirimarily for lestmg 

 toil circuits. The vertical section of the board provides jacks for 



