United States Patent 3123672
Publication Date:
03/03/1964
Other Classes:
380/259, 380/38, 455/116, 380/252
International Classes:
H04K1/02
US Patent References:
| 2851591 | Selective calling wireless transmission system | | | |
| 3020352 | Single sideband equipment for speech transmission | | | |
| 3056086 | Squelch circuit | | | |