| # | Country | Total Patents | |
|---|---|---|---|
| #1 | United States | 3 | |
| #2 | Canada | 2 | |
| #3 | Switzerland | 2 | |
| #4 | Germany | 2 | |
| #5 | France | 2 | |
| #6 | United Kingdom | 2 |
| # | Industry | |
|---|---|---|
| #1 | Audio-visual technology | |
| #2 | Machines |
| # | Technology | |
|---|---|---|
| #1 | Loudspeakers and microphones | |
| #2 | Unspecified technologies |
| # | Name | Total Patents |
|---|---|---|
| #1 | Lambert Schmidt | 3 |
| #2 | Schmidt Lambert | 2 |
| #3 | Radiotive Corporation The | 2 |
| Publication | Filing date | Title |
|---|---|---|
| GB210737A | Improvements in or relating to telephone apparatus | |
| US1646261A | Diaphragm | |
| US1452851A | Head receiver for telephones | |
| US1519811A | Telephone receiver or transmitter | |
| CA244042A | Telephone apparatus | |
| CA262009A | Loud speaker diaphragm |