GB1013594A
(en )
1965-12-15
Improvements in communication switching systems
GB982825A
(en )
1965-02-10
Class of service telephone system
SE327219B
(GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html )
1970-08-17
GB917017A
(en )
1963-01-30
Improvements relating to automatic telecommunication switching systems
SE310375B
(GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html )
1969-04-28
GB1029385A
(en )
1966-05-11
Circuit arrangement to control cross-point arrangements in telephone systems
US2410304A
(en )
1946-10-29
Automatic telephone system
US3193621A
(en )
1965-07-06
Telephone line finder
GB1130431A
(en )
1968-10-16
Communication switching systems
US3111560A
(en )
1963-11-19
Line circuit
GB725733A
(en )
1955-03-09
Improvements in or relating to circuits for use in automatic telephone systems
US2406053A
(en )
1946-08-20
Telephone system
GB1265084A
(GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html )
1972-03-01
GB990545A
(en )
1965-04-28
Telephone concentrator systems
US2707211A
(en )
1955-04-26
Adapter circuit
US2874224A
(en )
1959-02-17
Combined toll and free-service telephone trunking system
GB1032966A
(en )
1966-06-15
Private automatic branch exchanges
GB1139740A
(en )
1969-01-15
Improvements in or relating to automatic telephone exchanges
SE326470B
(GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html )
1970-07-27
US2199431A
(en )
1940-05-07
Telephone signaling system
GB707038A
(en )
1954-04-07
Improvements in or relating to marking circuit-arrangement for positioning a final selector switch
US2719882A
(en )
1955-10-04
Automatic telephone systems
ES283082A1
(es )
1963-02-01
Mejoras en sistemas conmutadores telefónicos automáticos
US2017888A
(en )
1935-10-22
Telephone system
GB813339A
(en )
1959-05-13
Improvements in or relating to electrical signalling systems