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US2206538A
(en)
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Telephone system
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US3462743A
(en)
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Path finding apparatus for switching network
|
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US2421919A
(en)
|
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Telephone routing system
|
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SE178373C1
(https=)
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|
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US1956371A
(en)
|
|
Telephone system
|
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US2367522A
(en)
|
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Signaling system
|
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US2878320A
(en)
|
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Circuit arrangement for telecommunication systems, in particular telephone systems
|
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US1593387A
(en)
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Telephone-exchange system
|
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US3271523A
(en)
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Coupling fields with single conductor through-switching of extensions over electromagnetically actuated contacts
|
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US2485351A
(en)
|
|
Automatic telephone system
|
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US2106360A
(en)
|
|
Telephone system
|
|
GB541768A
(en)
|
|
Communication exchange systems
|
|
GB479852A
(en)
|
|
Improvements in or relating to automatic or semi-automatic telephone systems
|
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US2428550A
(en)
|
|
Riziq |
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US1482618A
(en)
|
|
Telephone-exchange system
|
|
US2711444A
(en)
|
|
Junction diagram for automatic switching system
|
|
US2679552A
(en)
|
|
Cross-bar switch system with several markers
|
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US2574903A
(en)
|
|
Translator for shifted lines and parties
|
|
US2714629A
(en)
|
|
Marking circuit
|
|
US1612014A
(en)
|
|
Recording mechanism
|
|
US2013169A
(en)
|
|
Selecting switch for use in telephone systems
|
|
GB419189A
(en)
|
|
Improvements in and relating to telephone installations
|
|
US3271522A
(en)
|
|
Circuit arrangement for determining the call numbers of party line subscribers
|
|
US3066191A
(en)
|
|
Automatic telecommunication exchange
|
|
US3532824A
(en)
|
|
Control circuit for multistage crosspoint networks
|