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US2354682A
(en)
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Electric selection controlling circuit
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US2242776A
(en)
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Telephone system
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BE462894A
(enFirst)
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|
|
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US2237413A
(en)
|
|
Telephone system
|
|
US2235153A
(en)
|
|
Chain start circuit
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|
US1663747A
(en)
|
|
Telephone-exchange system
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|
US2023011A
(en)
|
|
Telephone system
|
|
US2005575A
(en)
|
|
Selective switch
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|
US2420713A
(en)
|
|
Impulsing circuit
|
|
US3919488A
(en)
|
|
Ring control circuit
|
|
US2082097A
(en)
|
|
Telephone system
|
|
US2517291A
(en)
|
|
Gas tube and resistor shunt to prevent distortion at impulse contacts
|
|
US1336098A
(en)
|
|
Telephone system
|
|
US1178471A
(en)
|
|
Automatic telephone-exchange apparatus.
|
|
US1521821A
(en)
|
|
Repeater for automatic telephone systems
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|
US1312688A
(en)
|
|
Plancxtrai |
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EP4601195A1
(fr)
|
|
Dispositif de commutation de charge
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|
US1244816A
(en)
|
|
Measured-service telephone system.
|
|
US1199158A
(en)
|
|
Call-distributing telephone system.
|
|
JPS6130790B2
(enFirst)
|
|
|
|
CH304201A
(fr)
|
|
Dispositif de commande par comparaison de potentiels.
|
|
BE332977A
(enFirst)
|
|
|
|
BE466091A
(enFirst)
|
|
|
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BE499046A
(enFirst)
|
|
|
|
CH272113A
(fr)
|
|
Dispositif de signalisation.
|