DK38054C
(en )
1927-10-17
Device for Secret Transmission of Signals, Speech and Other Messages.
FR32851E
(en )
1928-03-06
Secret telegraphy system
FR621470A
(en )
1927-05-12
Telegraph transmission system
FR662634A
(en )
1929-08-09
Improvements to transmission line checking devices, especially telegraph and telephone lines
DK42110C
(en )
1930-04-22
Device for Secret Transmission of Signals.
DK42622C
(en )
1930-07-21
Device for Secret Transmission of Signals.
DK43169C
(en )
1930-10-13
Device for Secret Transmission of Signals.
ES116963A1
(en )
1930-04-16
Verification procedure of telephone, telegraphic or signal lines.
DK35869C
(en )
1926-04-12
Earpiece for Telephones and similar Devices.
DK25198C
(en )
1919-11-17
Procedure and Apparatus for Transmitting Signals, Speech and Other Messages.
DK44396C
(en )
1931-07-27
Device for Secret Transmission of Electrical Signals.
DK42233C
(en )
1930-05-12
Automatically operating Telegraph Key for Sending Emergency Signals and the like.
ES90051A1
(en )
1924-10-16
Improvements in secret telephone and signal transmission systems.
FR602033A
(en )
1926-03-11
Improvements to the baudot telegraph system
FR615741A
(en )
1927-01-14
Pavilion for acoustic headphones of phonographs, telegraphs, telephones, radio telegraphs and radio telephones, etc.
DK38316C
(en )
1928-01-02
Submarine Telegraph System.
CH126054A
(en )
1928-06-01
Telephone transmission line.
DK31751C
(en )
1923-05-22
Audio Transmission Device for Phones.
DK40392C
(en )
1929-07-01
Selective Telegraphic Receiver.
DK34357C
(en )
1925-04-06
Device for telephone, possibly wireless, Voice transmission.
DK40851C
(en )
1929-09-30
Cone-shaped Membrane for Speakers and the like.
DK29064C
(en )
1921-12-27
Procedure and Apparatus for Transmitting Signals, Speeches, and Other Messages.
DK45453C
(en )
1932-03-29
Coupling device for Telephone system with Selector operation and Voice current amplifiers.
DK45748C
(en )
1932-05-30
Coupling device for Telephone system with Selector operation and Voice current amplifiers.
FR591147A
(en )
1925-06-29
Transmitter, amplifier and telephone translator