Method for preventing an unauthorized device from operating in an 800 MHz trunked radio communications system using channels 319 to 0
US7228130B1 · kind B1 · utility
2Cited by
10References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 30, 2005 |
| Grant date | Jun 5, 2007 |
| Priority date | — |
| Expiry date | Dec 6, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W76/20
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A receiving device in a trunked radio communications system determines a transmit frequency, wherein the transmit frequency is calculated by subtracting a voice channel number from 319, multiplying by a channel spacing and adding a base frequency to yield the transmit frequency, if the voice channel number is between 319 and 0. The receiving device determines a receive frequency by 851.0125 MHz+[(319−a voice channel number)*25,000 Hz], if the voice channel number is between 319 and 0. In any case, the voice channel number is communicated in an outbound signaling message defined by Motorola's 3600-baud radio trunking protocol.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.