公开(公告)号：US3573389A

公开(公告)日：1971-04-06

申请号：US3573389D

申请日：1968-12-18

Applicant: BELL TELEPHONE LABOR INC

Inventor： GREENSTEIN MARTIN R ,  ZAROUNI ALFRED

IPC: H04M1/677 ,  H04Q3/54 ,  H04M3/54

CPC classification number: H04Q3/54 ,  H04M1/677

Abstract: Special services, such as call transfer and abbreviated dialing, are provided by auxiliary circuits each uniquely associated with certain subscriber lines in a common control-switching system. The auxiliary circuit is arranged with shift registers to recognize the dialing of a predetermined code and to respond thereto by releasing and reenabling the common control switching equipment. On abbreviated dialing calls, the return of dial tone by the reenabled central office register enables the auxiliary circuit to outpulse the directory number of the desired station. On transfer calls, after dialing the access code, the subscriber primes the transfer feature by dialing the directory number of the transfer station. This number is then simultaneously stored in the auxiliary circuit and in the reenabled central office register. In either situation the call then progresses to completion in the normal manner.