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US3626107A
(en)
|
|
Three-way calling and call-waiting arrangements for step-by-step telephone systems
|
|
GB439323A
(en)
|
|
Improvements relating to automatic telephone and like selective systems
|
|
GB461082A
(en)
|
|
Improvements in or relating to telephone systems
|
|
US2137422A
(en)
|
|
Automatic switch
|
|
BE522048A
(enExample)
|
|
|
|
US1653782A
(en)
|
|
Testing system
|
|
US2575882A
(en)
|
|
Connecting device at crossbar switch for selection of connecting links
|
|
US3529098A
(en)
|
|
Two relay line circuit
|
|
US1560858A
(en)
|
|
Automatic telephone system
|
|
GB366143A
(en)
|
|
Improvements in or relating to telephone systems
|
|
SE185078C1
(enExample)
|
|
|
|
GB602388A
(en)
|
|
Improvements in electrical impulsing circuits
|
|
NO117189B
(enExample)
|
|
|
|
SE203324C1
(enExample)
|
|
|
|
GB533113A
(en)
|
|
Improvements relating to telephone and like signalling systems
|
|
US1361885A
(en)
|
|
Automatic telephone system
|
|
US1363268A
(en)
|
|
Telephone system
|
|
US1757224A
(en)
|
|
Rotary line-switch circuit
|
|
PL20191B1
(pl)
|
|
Urzadzenie telefoniczne.
|
|
SE129173C1
(enExample)
|
|
|
|
US2577740A
(en)
|
|
Telephone exchange system
|
|
US1902123A
(en)
|
|
Control circuit for switches for automatic telephone systems
|
|
GB431946A
(en)
|
|
Improvements in or relating to telephone systems
|
|
SE128982C1
(enExample)
|
|
|
|
SE128636C1
(enExample)
|
|
|