( 17992 of 17992 ) |
United States Patent | 3,558,829 |
Aro , et al. | January 26, 1971 |
A telephone central office switching system in which communication paths are established over crossbar switches controlled by line group markers and group selector markers and which includes special features trunks. Logic for the special features trunks, interoffice trunks, and operator's trunks are concentrated in supervisory control units having a wired program; bulk memory in the form of magnetic cores with magnetic drum backup, changeable from the outside world, is provided for storage of data relative to called number information received, number group and translation functions, status of special features trunks, class of calls, line and trunk identification, etc.; and in which registering, translating, sending, control of supervisory control units, and other functions are processor controlled by means of a stored program which is changeable from the outside world to provide modified operation or new features.
Inventors: | Aro; Enn (Galion, OH), Cheney; Thomas K. (Galion, OH), Dankowski; James J. (Galion, OH), Fearn; Clifford M. (Galion, OH), Nennerfelt; Carl B. (Galion, OH), Patterson; Albert D. (Galion, OH), Sharland; Robert W. (Galion, OH), Watts; James A. (Galion, OH) |
Assignee: |
North Electric Company
(Galion,
OH)
|
Appl. No.: | 04/736,634 |
Filed: | June 13, 1968 |
Current U.S. Class: | 379/275 ; 379/245; 379/246; 379/280; 379/288; 379/290 |
Current International Class: | H04Q 3/545 (20060101); H04q 003/54 () |
Field of Search: | 179/22(Cursory),18SP,18.211,18.9 |
3365548 | January 1968 | Lucas et al. |
3458662 | July 1969 | Hayes et al. |