FR680306A - - Google Patents
Info
- Publication number
- FR680306A FR680306A FR680306DA FR680306A FR 680306 A FR680306 A FR 680306A FR 680306D A FR680306D A FR 680306DA FR 680306 A FR680306 A FR 680306A
- Authority
- FR
- France
- 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
- H04M—TELEPHONIC COMMUNICATION
- H04M3/00—Automatic or semi-automatic exchanges
- H04M3/42—Systems providing special services or facilities to subscribers
- H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE1944283X | 1929-06-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| FR680306A true FR680306A (en) | 1930-04-26 |
Family
ID=7750643
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| FR680306D Expired FR680306A (en) | 1929-06-22 |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US1944283A (en) |
| BE (1) | BE363032A (en) |
| FR (1) | FR680306A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR948355A (en) * | 1942-12-31 | 1949-07-29 | Western Electric Co | Coupling device usable in wave transmission systems |
| US3135829A (en) * | 1959-10-09 | 1964-06-02 | Itt | Conference call circuit |
| US3891801A (en) * | 1974-01-21 | 1975-06-24 | Quindar Electronics | Four-way four-wire active bridge |
| US3885100A (en) * | 1974-05-31 | 1975-05-20 | Bell Telephone Labor Inc | Six-port conference amplifier circuit |
| US4008376A (en) * | 1975-10-17 | 1977-02-15 | Bell Telephone Laboratories, Incorporated | Loudspeaking teleconferencing circuit |
| US4289932A (en) * | 1979-10-15 | 1981-09-15 | Reed Roger R | Conferencing communications system |
-
0
- BE BE363032D patent/BE363032A/xx unknown
- FR FR680306D patent/FR680306A/fr not_active Expired
-
1930
- 1930-05-31 US US458441A patent/US1944283A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| BE363032A (en) | |
| US1944283A (en) | 1934-01-23 |