What is the purpose of an 'all call' channel?

[towhee_falconer]

Several fire departments that I have interest in scanning have channels that are described on the RRDB as "all call". I've programmed them into my scanner, and there was no traffic. The name could imply that they handle all of the calls, but that is clearly not happening this case.

 

[RaleighGuy]

Several fire departments that I have interest in scanning have channels that are described on the RRDB as "all call". I've programmed them into my scanner, and there was no traffic. The name could imply that they handle all of the calls, but that is clearly not happening this case.

All call channels are used to broadcast a message to all radios/talkgroups/frequencies, it has (typically) very little traffic. At work we use DMR radios, the upper management have the ability to transmit on the All Call channel but the worker radios do not. All radios scan the All Call channel for traffic, we might get one or two messages a night absent something important happening.

 

[mmckenna]

Like RaleighGuy, I have an 'all call' on my trunked system. Only our dispatchers a a very few specific users have access to it. It's just a way to reach all radio users at the same time with a broadcast type message. Users can't answer back, on my system. I could probably count the number of times its been used in the last 12 years without taking my shoes off.

 

[a417]

Had an all-call on our LTR way back when, was used once during a suspected high profile event when the dispatcher wanted everyone with a radio in town to know something. I think that was the only official time I heard it used in the 9 yrs i worked on that system.

The systems around me now usually only see activity on that channel when someone with collar plungers sits on a mic during an 'executive lunch'.

The most discussed use-case heard in committee meetings was "So if a non-custodial person manages to get a kid at school pickup, and we need everyone with a radio & eyes to look for a vehicle...". Usage usually depends on the skill level of the dispatchers on the mic at the time.

 

[towhee_falconer]

Like RaleighGuy, I have an 'all call' on my trunked system. Only our dispatchers a a very few specific users have access to it. It's just a way to reach all radio users at the same time with a broadcast type message. Users can't answer back, on my system. I could probably count the number of times its been used in the last 12 years without taking my shoes off.

That makes sense. Also, I am guessing, on trunked systems you could give an all call channel priority - which you would not do if anyone one the system could broadcast on it.

 

[a417]

That makes sense. Also, I am guessing, on trunked systems you could give an all call channel priority - which you would not do if anyone one the system could broadcast on it.

You absolutely can do that.

I know a couple of agencies that use the all-call as their dispatch talkgroup. The radios are always listening for the ATC group in that range, and the dispatchers play some noises over it and then send the heros on their way. You could be on any of the trunked talkgroups that radio has in it, and you'll always hear a dispatch go out.

 

[stantorres]

An example of the use of an all-call channel... every so often our dispatch center, or neighboring center, gets a call of a road rage where one motorist is pointing a gun at another. On I-75 a car traveling at high speed can go through 3 jurisdictions in a matter if minutes. Instead of transferring the caller every 3 minutes, you just go to the all-call channel and say "any units in the area of northbound i75 and crooks, caller on the line reports driver of a blue silverado just pointed a silver handgun at her"... "caller is passing south boulevard".... "now passing University Drive"... then you would have a PD unit say they have it in sight, and take it from there on their own talkgroup. The advantage is that multiple units from multiple agencies and multiple dispatch centers all get the information at the same time, and this lets everybody work together to see who is able to intercept. The first 2 jurisdictions might not have anyone available or close enough, but further down the line a neighboring jurisdiction heard it and was able to get into position. Pretty cool when it works.

 

[ofd8001]

Around our place the "ATG" or All Talk Group, is used for weather alerts. "Hey there's a tornado bearing down on us".

Also, they've been known to be used for fire scene emergency evacuations when conditions go bad. That way if someone happens to be on the wrong channel, they will still hear the message.

 

[N4DES]

In the system I previously managed we didn't utilize All-Call, but we have discipline specific Call talk-groups (LE, FR, and EM) that are used in conjunction with the interoperability working talk-groups. By policy all PSAP's in the County are required to maintain and monitor the disciplines that they dispatched for. In addition to hails from the field for all of the disciplines, LE Call is utilized for the verbal transmissions of active BOLO's and other in-progress calls that might cross jurisdictional boundaries. This operational policy has been in place since around 2001 and used daily.

 

[CrabbyMilton]

Several fire departments that I have interest in scanning have channels that are described on the RRDB as "all call". I've programmed them into my scanner, and there was no traffic. The name could imply that they handle all of the calls, but that is clearly not happening this case.

Often times these are used for special announcements. Weather bulletins, special notifications in regards to missing persons or crime alerts, special events, sad end of watch or happier retirement acknowledgements have been heard. Our airport TG, have an announcement TG which comes in handy during severe weather. If there is a lightning strike within whatever number of miles of the airport, they come on and broadcast it almost immediately. It's a good idea to keep those on there or even a special bank for those.

 

[ecps92]

That makes sense. Also, I am guessing, on trunked systems you could give an all call channel priority - which you would not do if anyone one the system could broadcast on it.

Motorola trunks have what they call - ATG (Announcement Talk Group) - limited traffic till the O-$h!t events or BOLO's
Saves time from having to do a multi-TG select, if programmed correctly

 

[CrabbyMilton]

Our county transit bus system had an old system from the 1970's that the dispatcher could make a group call to certain routes or the whole system if needed. Apparently a group call would cause the radio to emit a special sound as opposed to a individual call. Well some drivers just didn't know so when the dispatcher would be broadcasting the group call, there would be at least one driver giving his badge, route, run and bus number since he or she thought it was a regular call. Then the dispatcher would get mad and say... This is a group call. Do not talk just listen. The systems that have followed now use data messages.