TELlil'llOM: IN.IXSMISSIOX M.IIXIF..\.l\Cn 29 



nates in an dIVicc also (iiiiipin-d wiih ,i ii.insnii><'<iiiii inctMiriiig set 

 of the s.inK' t\ |H'. 



To illustrate tho application of this toll transmission test desk, 

 Fig. 2 shows seheinatieally an arrangement of four toll olVires having 

 circuits hetween them of the three general classes non-re|K\itere(l, 

 refK'atcritl aiul carrier. OlVices A anil 1) are e(|iiippe(l with trans- 

 mission measiirim; sets of the t\pe shown in I'ii;. 1. .\ l(>j;ical testing 



te*' r«o<«lTi^ Crcmf 



I* = 3 



S 



=D= 



H 



=|3 



o 



Fig. 2 — Schematic Diagram of Typical Tull Cin iiit Layout to Illustrate (ieneral 

 .Methotl of Testing Non-Rcpeatered, Rcpeatcrcd and Carrier Circuits 



proccthirc for the arrangement in Fig. 2 is for offices A and D to test the 

 non-repcatered circuits 1 to 4 and 10 to Vi by ha\ing thejn looped 

 two at a time at the distant terminal offices B and (". \W "iriangti- 

 lation measurements" on an%- three circuits in each group, the equi\- 

 alent of each indi\-idual circuit can be readily computed. 



For the circuits o to 9 extending between offices A and D equii)ped 

 with telephone repeaters or carrier, straightaway measurements 

 can be made in each direction with the two transmission measuring 

 sets pro%-idetl. Loop tests could, of course, also be made on the 

 circuits from either office A or U, but this would require cutting 



