CARD TRANSLATOR FOR NATIONWIDE DIALING 1039 



to the decoder, and then, as directed subsequently by the marker, to 

 send digits ahead as may be required. 



The decoder's function is to receive the code digits, either 3, 4, 5 or 6, 

 from the sender and to submit them to the translator for translation 

 and to make selections of alternate routes as required to route the call 

 to the destination. The decoder also gives instructions to the sender 

 and marker to enable them to carry out their functions. 



The marker gets access to an outgoing trunk group through the trunk 

 block connector and selects an idle outgoing trunk in this group, then 

 chooses an idle linkage between the incoming and outgoing trunks, 

 operates the crossbar switches to close the transmission path, and gives 

 the sender information for pulsing ahead as may be required. 



The operation of these common control circuits is briefly as follows. 

 On the arrival of a call the incoming trunk is connected to a sender 

 through the sender link frame. When the code has been registered the 

 sender makes connection to the decoder through the decoder connector 

 cu-cuit. The decoder passes the code to the translator for translation. 

 There is a translator associated with each decoder which contains the 

 three-digit cards for the local offices and area codes, also perhaps some 

 six-digit code cards. However, most of the six-digit cards (there may be 

 several thousands of them) will be in a group of foreign area translators 

 used in common by all decoders. The decoders obtain information from 

 the area code card for selecting the particular one of these translators. 

 Connection to them is made through an appropriate translator connector. 

 The translator gives information for the selection ot an outgoing trunk 

 and passes other information for routing the call both to the decoder as 

 well as to the marker. The marker proceeds with trunk test and the 

 operation of the switches to establish the connection. When the proper 

 information has been given to the marker, then the decoder and trans- 

 lator release from that call. When the marker has given information to 

 the sender for routing the call and has established the talking connec- 

 tion, the marker releases. The sender releases as soon as it has finished 

 pulsing ahead. In this way these common control units handle many calls 

 in rapid succession. 



SIX DIGIT TRANSLATION 



This feature is needed in nationwide dialing because from a particular 

 CSP to points in another numbering area there may be several routes or 

 trunk groups. To reach a point in such an area it is necessary that the 

 office code as well as the area code be translated to select the route to 



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