878 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1952 



The class holes indicate such things as type of pulsing and nature of 

 the signaling channel used on the trunk group out of the office. 



The area code control holes in the third line are to tell the decoder 

 what to do al)out dropping or spilling forward an area code registered 

 in the sender or supplying an area code when none is registered. This 

 information is needed primarily in corniection with alternate routing. 



The alternate route pattern number holes tell the decoder at what 

 point to enter its chain of alternate route relays for the first choice 

 alternate. Provision is made for a maximum of 100 entry points. 



The holes on the fourth line are for making proper disposition of calls 

 when no circuits are available on any routes, telling how many digits 

 to expect on certain calls and other items of a detailed technical nature. 



The code conversion holes on the fifth line supply the arbitrary digits 

 to replace code digits on calls routed through step-by-step TO's or 

 TC's. Provision is made for one, two or three digits as required. 



The variable spill control holes in the sixth line tell whether to spill 

 all digits received, skip the first three code digits or skip six code digits. 



The remaining holes define the location on the equipment of the test 

 leads for the trunk group o\'er which the call will be routed. 



The notches around the edges are used for proper positioning and re- 

 moval of cards. 



An individual card is removed from the stack by first keying the code 

 to cause it to drop so that it may be identified. Since a card can easily be 

 located in this manner it is unnecessary to keep cards in any ordered 

 position in the box. 



At least one translator is provided in every decoder. It contains the 

 cards for all offices in the home numbering area of the CSP, for certain 

 operator codes, the single three-digit card for each toll numbering area 

 and a card for each toll line group out of the office that can be used as 

 an alternate route. If there are other areas to which the volume of traffic 

 is very high and for which six-digit translation is required the cards for 

 those areas are put in a second machine in each decoder. Cards for other 

 areas are put in foreign area translators common to the office and acces- 

 sible to all decoders on a one-at-a-time basis. An emergency translator 

 is provided to permit removal of all cards to it from any translator which 

 may require prolonged repair work. 



6. Traffic Control Panel 



The traffic control panel is located in the operating room. The ecjuip- 

 ment in it consists of a key for each group used as an alternate route. 

 When a particular key is operated no alternate routed traffic will be 



