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US2452578A
(en)
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Telephone system utilizing a register controller
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US2504708A
(en)
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Selecting-switch for use in telephone systems
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SE191734C1
(enExample)
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US2237413A
(en)
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Telephone system
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US2485351A
(en)
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Automatic telephone system
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US2999131A
(en)
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Group selection stage for automatic telephone exchanges
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US2176340A
(en)
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Telephone system
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US2195309A
(en)
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Telephone system
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US2559601A
(en)
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Automatic selector control system
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US1568039A
(en)
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Telephone-exchange system
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US2699467A
(en)
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Telephone system and a relayless line circuit and circuits in cooperation therewith for extending a call
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US2668876A
(en)
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Double-selection electronic switching system
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US1963929A
(en)
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Telephone system
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US2668194A
(en)
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Finder-allotter circuit for telephone systems
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US875951A
(en)
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Controlling mechanism for automatic exchanges.
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US1917390A
(en)
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|
Telephone system
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US1464084A
(en)
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|
Telephone-exchange system
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US2787662A
(en)
|
|
Automatic telephone system having switching means for routing calls in different traffic directions
|
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DE693535C
(de)
|
|
Schaltungsanordnung fuer Fernsprechanlagen
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US1312126A
(en)
|
|
Planociraph co |
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US1550783A
(en)
|
|
Telephone-exchange system
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US1109620A
(en)
|
|
Telephone-exchange system.
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US1337740A
(en)
|
|
Telephone-exchange system
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US1147390A
(en)
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|
Switches and circuits for automatic telephone-exchanges.
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US1284996A
(en)
|
|
Semi-automatic telephone-exchange system.
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