Browse Prior Art Database

TRUNKING EAVESDROP RADIO

IP.com Disclosure Number: IPCOM000007522D
Original Publication Date: 1995-Nov-01
Included in the Prior Art Database: 2002-Apr-03
Document File: 1 page(s) / 53K

Publishing Venue

Motorola

Related People

Hans Christopher Sowa: AUTHOR

Abstract

SYSTEM BACKGROUND: The system is a 2-way radio trunking system such as Smartnet or SmartZone. THE PROBLEMS: A radio user needs to be monitored for a crimi- nal investigation or to train other radio users. The radio user has affiliation turned off, changes talk groups (TG), or enters private calls thus making monitoring diicult. Monitoring this radio user would require all voice channels in the system to be monitored.

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Technical Developments

TRUNKING EAVESDROP RADIO

by Hans Christopher Sowa

eavesdropped radio would send the receive active ISW every time it joined, a call. The transmit LED on the radio would not light to hide the fact that the receive active ISW was sent. The trunking control- ler would send an Outbound Signalling Work (OSW) that would indicate what TG and hequency the radio being eavesdropped was receiving on. Radios monitoring the eavesdropped radio would see the OSW and follow the radio to the channel to receive with the eavesdropped radio. The trunking control- ler would send OSW updates as to where the eavesdropped radio was at all times.

  If the eavesdropped radio changed TGs before the channel dropped, the trunking controller would send a low speed (LS) indication that the radio had left. This would require ,the eavesdropped radio to send another hidden ISW when it got back to the control channel.

THE SOLUTION: Radios monitoring the eavesdropped radio would also follow the radio into private calls. In trunking A command would be sent to the eavesdropped scan, the eavesdropped radio would also send a hid- radio from a central location to activate a new receive den receive active ISW before listening to a TG in active Inbound Signalling Word (ISW). The its scan list.

SYSTEM BACKGROUND:

The system is a 2-way radio trunking system such as Smartnet or SmartZone.

THE PROBLEMS:

  A radio user needs to be monitored for a crimi- nal investigation or to train other ra...