US3555196A
(en )
1971-01-12
Telephone switching system with programmed auxiliary control for providing special services
FR1426970A
(fr )
1966-02-04
Système pour le traitement de informations commandé par programme
US3440355A
(en )
1969-04-22
Time division signaling arrangement
US2201573A
(en )
1940-05-21
Telephone system
US1568039A
(en )
1925-12-29
Telephone-exchange system
US3855420A
(en )
1974-12-17
Supervisory circuit
GB208509A
(en )
1924-10-30
Improvements in or relating to telephone systems
US3705275A
(en )
1972-12-05
Telephone trunk testing system
GB206930A
(enExample )
GB1360477A
(en )
1974-07-17
Telephone systems
US2302587A
(en )
1942-11-17
Telephone trunking system
US3513262A
(en )
1970-05-19
All-busy trunk signalling in common control telephone switchboards
US3488751A
(en )
1970-01-06
Telecommunication exchange system with provision for special and normal facility operation through a switching network
US3521003A
(en )
1970-07-21
Automatic interception and transfer of calls
US3211838A
(en )
1965-10-12
Traffic between private automatic branch telephone exchanges
US3636263A
(en )
1972-01-18
Telephone switching system
US3883698A
(en )
1975-05-13
Arrangement for handling permanent signals
US2938959A
(en )
1960-05-31
Relayless line circuit
US3205313A
(en )
1965-09-07
Circuit arrangement in an automatic telephone system for rendering the subscriber's number independent of his location in the selector multiple
US3286037A
(en )
1966-11-15
Remote line concentrator switching network
US3466401A
(en )
1969-09-09
Telephone exchange with interworking of switching units of different types
US1891254A
(en )
1932-12-20
Automatic telephone system
US1836589A
(en )
1931-12-15
Rural telephone system
US4058684A
(en )
1977-11-15
Apparatus for direct line switching
Glenner et al.
1966
System design parameters of overseas AUTOVON switching system