. The Bell System technical journal . (059) (076) (097) CALLED NUMBER2345 IN MAIN 2CENTRAL OFFICE TYPICAL DIGITS \ \ \ \ \ \ DIRECT DIAL 0590760971572345 0760971572345 0971572345 1572345 T COMMON CONTROL 217 Maz 2345 217 MA2 2345 217 MA2 2345 MA2 2345 |; 2345 : Fig. 6—Numbering with direct dial control and common control COMMON COVrUOL SW 1 !( 111 .\,fits. (\dls originating in a common control system can use office namecodes (such as MA 2 for calls to the ]\IAin 2 oflice) to n^ach destinations\ia step-by-step switching equipment where route codes (such as 157)ai-e widely used.
. The Bell System technical journal . (059) (076) (097) CALLED NUMBER2345 IN MAIN 2CENTRAL OFFICE TYPICAL DIGITS \ \ \ \ \ \ DIRECT DIAL 0590760971572345 0760971572345 0971572345 1572345 T COMMON CONTROL 217 Maz 2345 217 MA2 2345 217 MA2 2345 MA2 2345 |; 2345 : Fig. 6—Numbering with direct dial control and common control COMMON COVrUOL SW 1 !( 111 .\,fits. (\dls originating in a common control system can use office namecodes (such as MA 2 for calls to the ]\IAin 2 oflice) to n^ach destinations\ia step-by-step switching equipment where route codes (such as 157)ai-e widely used. The translating e(|uii)meiit at tiie common control ofhcecan be arranged to substitute arbitrary digits for the office name codedigits or in some cases to prefix arbitrarj^ digits ah(\i(l of the callednumber. The arbitrary digits substituted or prefixed conform to there(iuirements of the office using route codes. In Fig. 6, office C whenequipped with common controls could be arranged to convert MA 2 to157, a
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
