DK35112C
(en )
1925-10-05
Procedure for Reducing Cross Speech by Telephone Double Wires and Duplex Speech Circuits.
DK39685C
(en )
1929-01-07
Procedure for Reducing Cross Speech and Listening in Telephone Double and Duplex Cables.
DK39709C
(en )
1929-01-21
Procedure for Compensating Telephone Dual Circuits for Reducing Cross Speech.
DK39710C
(en )
1929-01-21
Procedure for Compensating Telephone Double Circuits for Reducing Cross Speech.
DK35436C
(en )
1925-12-28
Procedure for Reducing Cross Speech in Telephone Cables.
DK34950C
(en )
1925-08-31
Procedure for Reducing Cross Speech in Telephone Cables.
DK33216C
(en )
1924-05-19
Procedure for Pupinizing High Frequency Telephone Cables.
ES70366A1
(en )
1919-09-01
Telephone hearing.
DK39558C
(en )
1928-12-03
Procedure for Abolition of Cross Speech in Telephone Cables.
FR555826A
(en )
1923-07-06
Improvements to microphones for telephony, radiotelegraphy and apps
AT89490B
(en )
1922-09-25
Telephone system.
DK34337C
(en )
1925-03-30
Telephone system.
DK37349C
(en )
1927-04-11
Telephone system.
DK37946C
(en )
1927-09-19
Telephone system.
FR518414A
(en )
1921-05-26
phone earpiece
DK27616C
(en )
1921-05-17
Sound suit for voice machines and the like.
DK30899C
(en )
1922-12-11
Line selector telephone.
DK32723C
(en )
1924-01-14
Procedure for the manufacture of boats, ships and other watercraft.
DK32036C
(en )
1923-07-30
Device for Antennas for Wireless Telegraphy and Telephony.
AT91060B
(en )
1923-01-25
Additional amplifier device for any telephone set.
DK30715C
(en )
1922-11-20
Telephone Sound Box for Dictaphones, Telephographers and similar Devices.
DK25012C
(en )
1919-09-15
Microphone.
ES71614A1
(en )
1920-02-16
Microphone.
ES71769A1
(en )
1920-03-01
Improvements in telephone lines.
DK28939C
(en )
1921-12-12
Procedure for the Manufacture of Nickel and Copper.