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GB1180140A
(en)
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|
Automatic Signal Transmission System
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|
US3941943A
(en)
|
|
Privacy circuit for key telephone systems
|
|
PL62629B1
(enrdf_load_stackoverflow)
|
|
|
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US4794640A
(en)
|
|
Switching control apparatus for intercom-telephone sets
|
|
US3156775A
(en)
|
|
Telephone converter
|
|
US4214127A
(en)
|
|
Intrinsically safe telephone network
|
|
US3689700A
(en)
|
|
Subscriber loop extension unit
|
|
GB959641A
(en)
|
|
A unit for causing an auxiliary telephone to ring if a main telephone is not answered
|
|
US1802675A
(en)
|
|
Intercommunicating telephone and signal system
|
|
JPS54114011A
(en)
|
|
Loudspeaker telephone device
|
|
US2356031A
(en)
|
|
Telephone substation apparatus
|
|
US1293060A
(en)
|
|
Telephone system.
|
|
US1272432A
(en)
|
|
Relay.
|
|
EP0235883A1
(en)
|
|
Telephone intercom device
|
|
US2423127A
(en)
|
|
Subscriber's station for telephone systems
|
|
SU129676A1
(ru)
|
|
Устройство искробезопасной телефонной св зи ЦБ
|
|
US4166928A
(en)
|
|
Loop, dial pulse and ring trip detection circuit
|
|
GB2266430A
(en)
|
|
Call connection priority designator
|
|
US1907660A
(en)
|
|
Telephone substation circuit
|
|
PL62296B1
(enrdf_load_stackoverflow)
|
|
|
|
US4868847A
(en)
|
|
Telephone intercom device
|
|
US2848553A
(en)
|
|
Ringing device for telephone systems
|
|
JPS5644257A
(en)
|
|
Telephone set
|
|
US3217110A
(en)
|
|
Extension telephone system and actuator
|
|
SU1179553A1
(ru)
|
|
Абонентский комплект
|