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City and County of Honolulu Public Safety System is no longer comprised of just 50 or more frequencies for each department. It's now comprised of multiple control channels and voice channels throughout 10 antenna sites around Hawaii Island that provide coverage to all agencies islandwide. 

 

 

So the question asked what is the difference between Talkgroups, Control Channels, and Voice Channels? 

 

Control channels:

In essence, a trunked radio system is a packet switching computer network. Users' radios send data packets to a computer, operating on a dedicated frequency — called a control channel — to request communication on a specific talk-group. The controller sends a digital signal to all radios monitoring that talkgroup, instructing the radios to automatically switch to the frequency indicated by the system to monitor the transmission. After the user is done speaking, the users' radios return to monitoring the control channel for additional transmissions.

This arrangement allows multiple groups of users to share a small set of actual radio frequencies without hearing each other's conversations. Trunked systems primarily conserve limited radio frequencies and also provide other advanced features to users.

 

Talkgroups:

A talkgroup is an assigned group on a trunked radio system. Unlike a conventional radio which assigns users a certain frequency, a trunk system takes a number of frequencies allocated to the system. Then the control channel coordinates the system so talkgroups can share these frequencies seamlessly. The purpose is to dramatically increase bandwidth. Many radios today treat talkgroups as if they were frequencies since they behave like such. For example, on a radio scanner, it is very common to be able to assign talkgroups into banks or lock them out, exactly like that of conventional frequencies.(Example: The system detects HPD Officer communicating to HPD Dispatch from Waikiki showing the ID tag of HPD Waikiki with a radio ID tag of that user's radio.)

 

Radio ID is the assigned number of that radio that is programmed into the system identifying what agency it belongs to and who is it specifically assigned to. (Example: 8001001 is the Radio ID for HPD Dispatch console in Hilo)

 

 

*Note: We do not suggest you buying an off-hand digital radio (Motorola, Tait, etc.) as a scanner and if you do, there are legal implications behind it, even if it's only strictly for listening purposes only. It emits a signal and radio ID where radio maintenance personnel can turn that signal off once detect as an unauthorized Radio ID and may lead to legal persecution and fines under state, county, and federal law if caught.