US2206538A
(en )
1940-07-02
Telephone system
US3462743A
(en )
1969-08-19
Path finding apparatus for switching network
US2421919A
(en )
1947-06-10
Telephone routing system
SE178373C1
(OSRAM )
1962-01-01
US1956371A
(en )
1934-04-24
Telephone system
US2367522A
(en )
1945-01-16
Signaling system
US2878320A
(en )
1959-03-17
Circuit arrangement for telecommunication systems, in particular telephone systems
US1593387A
(en )
1926-07-20
Telephone-exchange system
US3271523A
(en )
1966-09-06
Coupling fields with single conductor through-switching of extensions over electromagnetically actuated contacts
US2485351A
(en )
1949-10-18
Automatic telephone system
US2106360A
(en )
1938-01-25
Telephone system
GB541768A
(en )
1941-12-10
Communication exchange systems
GB904463A
(en )
1962-08-29
Improvements in or relating to arrangements for seeking, selecting and setting up free transmission paths in coupling panels in a telecommunication system
GB479852A
(en )
1938-02-11
Improvements in or relating to automatic or semi-automatic telephone systems
US2428550A
(en )
1947-10-07
Riziq
US1482618A
(en )
1924-02-05
Telephone-exchange system
US2711444A
(en )
1955-06-21
Junction diagram for automatic switching system
US1340935A
(en )
1920-05-25
Telephone-exchange system
US2574903A
(en )
1951-11-13
Translator for shifted lines and parties
GB700341A
(en )
1953-12-02
Automatic toll-ticketing system
US2714629A
(en )
1955-08-02
Marking circuit
US1714718A
(en )
1929-05-28
A cobfosation of dela
US1612014A
(en )
1926-12-28
Recording mechanism
US2013169A
(en )
1935-09-03
Selecting switch for use in telephone systems
GB419189A
(en )
1934-11-07
Improvements in and relating to telephone installations