Method for preventing an unauthorized device from operating in a 800 MHz trunked radio communications system
US7546085B1 · kind B1 · utility
0Cited by
10References
20Claims
0Family size
Assignee
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Key dates
| Filing date | Aug 30, 2005 |
| Grant date | Jun 9, 2009 |
| Priority date | — |
| Expiry date | Oct 21, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W48/02
- 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 759, multiplying by a channel spacing and adding a base frequency to yield the transmit frequency. The receiving device determines a receive frequency by a base frequency+[(759−a voice channel number)*25,000 Hz], where the base frequency is at least one of 851.0125 MHz, 851.0250 MHz, and 851.000 MHz. 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.