FR660479A - Perfectionnements aux microtéléphones - Google Patents
Perfectionnements aux microtéléphonesInfo
- Publication number
- FR660479A FR660479A FR660479DA FR660479A FR 660479 A FR660479 A FR 660479A FR 660479D A FR660479D A FR 660479DA FR 660479 A FR660479 A FR 660479A
- Authority
- FR
- France
- Prior art keywords
- microtelephones
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R21/00—Variable-resistance transducers
- H04R21/02—Microphones
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/02—Constructional features of telephone sets
- H04M1/03—Constructional features of telephone transmitters or receivers, e.g. telephone hand-sets
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
- Telephone Set Structure (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB28960/27A GB304843A (en) | 1927-10-31 | 1927-10-31 | Improvements in or relating to telephone hand sets |
Publications (1)
Publication Number | Publication Date |
---|---|
FR660479A true FR660479A (fr) | 1929-07-11 |
Family
ID=10283971
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
FR660479D Expired FR660479A (fr) | 1927-10-31 | 1928-09-15 | Perfectionnements aux microtéléphones |
Country Status (4)
Country | Link |
---|---|
US (1) | US1779490A (fr) |
FR (1) | FR660479A (fr) |
GB (1) | GB304843A (fr) |
NL (1) | NL25706C (fr) |
-
0
- NL NL25706D patent/NL25706C/xx active
-
1927
- 1927-10-31 GB GB28960/27A patent/GB304843A/en not_active Expired
-
1928
- 1928-09-15 FR FR660479D patent/FR660479A/fr not_active Expired
- 1928-12-12 US US325614A patent/US1779490A/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
GB304843A (en) | 1929-01-31 |
US1779490A (en) | 1930-10-28 |
NL25706C (fr) |
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