354 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



trunk number 21-49 combine to give a number 



80349 



where the underUned digits represent the set of junctors (see Fig. 24). 



In the general case, the junctors of a set may terminate on either the 

 left or right half of a trunk link frame junctor switch. When the channel 

 cards are made out preparatory to a throwdown study, the junctor 

 numbers are assigned to cards of one of two colors (same as trunk link 

 cards) depending upon whether it is left or right connection. Thus, in 

 picking the three channel cards for a match, the choice of trunk link 

 card depends upon, and must be the same as, the color of the junctor 

 card. 



Normally the channel cards are kept in filing sections at the match 

 position as shown on Fig. 23. Before the matching operation is physically 

 performed, the operator has available on a match ticket the line-trunk 

 composite number. In the example shown on Fig. 26 this number is 



80349 



The digits 803 identify the line link card; the digits 034, the junctor 

 card; and the digits 49, together with the junctor card color, identify the 

 trunk link card. The operator removes the cards from the file, stacks 

 them, and places them in a slot associated with the particular marker 

 until the match signal is received. At that time, the operator picks the 

 lowest numbered free channel in the stack, marks it busy and enters 

 the channel number on the match ticket for record. 



Each channel must be released at the same time that the line and trunk 

 with which it is associated are removed from holding. Since release times 

 for lines and trunks are entered on the assignment position holding 

 time detector, this latter detector is used to signal release times to the 

 match operator. The match operator maintains all her established match 

 tickets in release time sequence with the earliest time on top of the 

 pile. The lighting of a signal lamp indicates that the channel identified 

 by the top ticket should be restored to normal. 



A channel release condition which the match operator must recognize 

 without a special signal occurs at the marker release time on intraoffice, 

 outgoing, partial dial and no dial calls. At this time the register channel 

 associated with the call must be dismissed. The operator will have 

 received from the marker operator the register channel ticket involved 

 and must restore the channel to normal before answering any new 

 signal. 



