.«x /</•/./. sysriiM inciiMc.ii. joikx.ii. 



both sNsU-ins an- in iipi-raliiiii in ilu- s;inic- i-xchan^i.' area are generally 

 ma<le from the manual otVue, liie loops being dialed from the A 

 switchboani, while trunks l)et\veen two machine switching offices 

 are tested from the outgoing end of the trunks. 



Fig. 8 shows a 3-A transmission measuring set as used in a machine 

 switching office ready for making tests on district selectors. To 



'•""K- 8— lllu-tr.iliiin nf a .V.\ rr.iiisinissiuii .MtasiiriiiK Sit. Sil up in a I'aiul Macliinc 

 SwilihiiiK Dfl'ut for Testing District Selectors 



illustrate the general methrwl of testing panel niacliine switching 

 circuits, the u|)iK-r diagram of l"ig. !» shows the schematic arrange- 

 ment for measuring trunks between two panel machine switching 

 offices. The transmission measuring set is located at office A, and 

 ( rinnection made to the outgoing end of the trunks to office B through 

 the test jacks .it the trouble desk. A standard selector test set used 



