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US2951125A
(en)
|
|
Electronic switching network
|
|
US20210119444A1
(en)
|
|
Hvdc transmission schemes
|
|
US2421919A
(en)
|
|
Telephone routing system
|
|
SE178299C1
(OSRAM)
|
|
|
|
SE451169B
(sv)
|
|
Ledningsstyrkrets for en tyristorstromriktare
|
|
US2315705A
(en)
|
|
Testing and selecting system
|
|
US2291036A
(en)
|
|
Selecting system
|
|
US3129293A
(en)
|
|
Automatic telecommunication switching systems
|
|
US2300505A
(en)
|
|
Selective system
|
|
US2946855A
(en)
|
|
Electrical circuit for communication networks
|
|
US1691410A
(en)
|
|
Automatic telephone system
|
|
US2367522A
(en)
|
|
Signaling system
|
|
US2409586A
(en)
|
|
Automatic telephone system
|
|
US2878320A
(en)
|
|
Circuit arrangement for telecommunication systems, in particular telephone systems
|
|
US3204037A
(en)
|
|
Automatic telecommunication exchanges
|
|
US3395253A
(en)
|
|
Telecommunication coordinate relay switching systems having auxiliary holding means
|
|
US2294457A
(en)
|
|
Selective system
|
|
US2299898A
(en)
|
|
Telephone system
|
|
US1687669A
(en)
|
|
Trunk-testing circuits for selector switches
|
|
US2714629A
(en)
|
|
Marking circuit
|
|
US1541386A
(en)
|
|
Machine-switching telephone-exchange system
|
|
US2552792A
(en)
|
|
Telephone system
|
|
US3444327A
(en)
|
|
Idle test unit
|
|
US2338642A
(en)
|
|
Testing and signaling system
|
|
US3536847A
(en)
|
|
Crosspoint operating circuit
|