EDACS Multiselect

[kyparamedic]

How do EDACS multiselect calls work? I thought that all the talkgroups that were selected listened on the same frequency. However, I was told that on our system each talkgroup that was selected went to its own frequency. This doesn't seem very efficient as it ties up a limited number of frequencies for the same thing. Do Motorola systems do this as well?

On our portables we can go to a specific talkgroup that broadcasts to all 4 of our talkgroups. What is this? On the receiving radios they display "FLEET" on the LCD screen.

 

[ElroyJetson]

Review the basics of trunking. No, the selected talkgroups are not all on the same frequency.

The system dynamically assigns calls to any available frequency in the pool, as needed. The same talkgroup will appear on every channel of the system, in time.

All trunking systems do this.

Fleet call will broadcast a call to all associated talkgroups within that fleet. It's to send messages to all personnel regardless of what specific talkgroups within your agency that they're monitoring at the moment. That way, if you have different personnel listening
to different talkgroups but the message has to be heard by EVERYBODY, it IS.


Elroy

 

[kyparamedic]

Thanks. I thought one of the advantages was the ability to broadcast to multiple talkgroups without tying up multiple channels. So when you do a fleet call, all talkgroups listen to the same channel, correct? But on a multiselect, each talkgroup selected listens on a separate channel. In this case you are then limited to how many talkgroups you can select depending on the number of physical channels allocated to your system. Do I have that right?

I thought I read somewhere that Smartnet systems allow you to do something a little different when it comes to fleet calls or their version of it. Like setting up individual groups of users that cannot be done on EDACS.

Thanks.

 

[wlmr]

Can't speak for EDACS.

To answer the Motorola trunked equivalent at least as far as it relates to 9600 P25, The basic start is each talkgroup is assigned a frequency. See the basics on trunking to understand that talkgroups are assigned frequencies on the fly, no tallkgroup is ALWAYS sent to the same frequency every time.

If you select a Multigroup, all radios on talkgroups assigned via the system to that multigroup are all told to go the the same frequency. The only exception would be if the multigroup has a mix of clear and encrypted talkgroups. In that instance, clear talkgroups all get sent to one frequency, encrypted to another.

If a dispatcher selects more than one talkgroup to transmit on via their console, or puts multiple talkgroups into a patch group, the same thing happens as with the multigroup description.

If you need more detail than that as far as non-EDACS trunking systems goes, I bet that the moderators will appreciate it if you ask in the other system's forum.

I am surprised that EDACS trunking would act in the way I seem to be understanding via previous posts above in this thread. Seems to be a rather inefficient way to assign a finite number of trunked frequencies.

 

[kyparamedic]

wlmr, that's what I was getting at. Since EDACS is supposed to be more efficient than Smartnet, or so I've heard, it's certainly not very efficient to assign each talkgroup a separate frequency when dispatching across multiple groups. One of the radio guys for our system said it can be done, but our system is not setup that way. (They also took ICALL out of our radios when our system was rebanded. He said they don't have it setup to give higher priority to talkgroups so we could tie up the system using ICALLs). So when they're broadcasting an amber alert (don't get me started on that), we may not be able to talk to the hospital because the number of available frequencies is exhausted. I wonder if it has anything to do with the fact we're using Zetron consoles instead of the M/A-COM Maestro console.

 

[EDACSTECH]

wlmr, that's what I was getting at. Since EDACS is supposed to be more efficient than Smartnet, or so I've heard, it's certainly not very efficient to assign each talkgroup a separate frequency when dispatching across multiple groups. One of the radio guys for our system said it can be done, but our system is not setup that way. (They also took ICALL out of our radios when our system was rebanded. He said they don't have it setup to give higher priority to talkgroups so we could tie up the system using ICALLs). So when they're broadcasting an amber alert (don't get me started on that), we may not be able to talk to the hospital because the number of available frequencies is exhausted. I wonder if it has anything to do with the fact we're using Zetron consoles instead of the M/A-COM Maestro console.

The Zetron console is the issue. It is not a true network console but has rack mounted mobile radios with a group ID assigned to each. When you select more than one module from your console display to simulselect or patch, the EDACS system thinks that several radios are transmitting at the same time and assignes working channels at the site to each radio. If you had a Maestro console and CEC switch, you could patch as many group modules together and the system would assign an SAID or system assigned ID as the group and only one repeater would be in use for all groups. As for the ICAlls, If your system includes a CSD Server, you have the ability to control how many ICALLs can take place at one time so you can allow ICALLs without loosing the ability to get your important group calls out when needed. Amber alert and other type calls that need to be sent to everyone on the system should use a "SYSTEM ALL CALL" or "AGENCY CALL" or even "FLEET CALL" depending on your system design and who you share the system with etc. Any of these calls only use one repeater if setup properly.

 

[kyparamedic]

Ok, that makes sense. Dispatch shows up as GR 1001 which explains the group ID. What is the difference between a group ID and individual ID if it's still just a mobile radio that is transmitting? I guess they don't want to do an ALL CALL because they would tie up every talkgroup (right?) rather than just the primary TG for each agency. AGENCY CALL also wouldn't work since it's for multiple agencies. I thought the radio tech said it could be setup to only use one frequency, maybe that's only if we got new consoles.

 

[EDACSTECH]

Ok, that makes sense. Dispatch shows up as GR 1001 which explains the group ID. What is the difference between a group ID and individual ID if it's still just a mobile radio that is transmitting? I guess they don't want to do an ALL CALL because they would tie up every talkgroup (right?) rather than just the primary TG for each agency. AGENCY CALL also wouldn't work since it's for multiple agencies. I thought the radio tech said it could be setup to only use one frequency, maybe that's only if we got new consoles.

GID is programmed in radios that will operate as a department or team. One radio talks and all others with the same GID listen. LID is a different ID for each radio in an EDACS system, kinda like each telephone has a different phone number. When an EDACS radio makes a group call, the system gets a request that LID "1000" wants to call GID "497". All radios with GID 497 will unmute and receive the call with their display showing LID 1000 was the caller. On an Indiv call, LID "1000" may call LID "1001" and only radio "1001" will unmute and receive the call. An agency type EDACS call, if your system was configured properly, could be used to call every radio in a city or county. In my system, Ocean City has several thousand radios issued on agency-1 and Worcester County has several thousand radios issued on agency-3. Ocean City could make an agency call to all city radios while all Worcester County radios work normally at the same time. EDACS and other trunked systems can do a lot if they are configured and understood. A good system manager make all the difference.

 

[kyparamedic]

Will the way our system is currently setup using the mobile radios allow ALL CALLS and AGENCY CALLS?

Also, what changes are made when ProScan is added? Currently we operate a multi-cast system with 2 repeaters. We have to manually switch between the two. There is a 3rd one being built and when it is, our radios will automatically switch to the best tower. They said it will cost like $30k to upgrade dispatch.

 

[EDACSTECH]

Will the way our system is currently setup using the mobile radios allow ALL CALLS and AGENCY CALLS?

Also, what changes are made when ProScan is added? Currently we operate a multi-cast system with 2 repeaters. We have to manually switch between the two. There is a 3rd one being built and when it is, our radios will automatically switch to the best tower. They said it will cost like $30k to upgrade dispatch.

Most likely all you would have to do is configure one radio, attached to your zetron console , to make an agency or all call. Your Proscan question depends on many factors in the design and setup of your radio sites and settings in each radio. Don't expect Proscan to work like a cell phone handoff. Most multisite systems are designed to overlap so you try not to have dead areas. This overlap means that your radios receive two or more signals at different levels as you move around. The radio programmer has to tell the radio what signal level to change sites. This works better on paper than in real life. The greater the separation between sites, with a clear break in coverage will result in better Proscan operation.

 

[kyparamedic]

Yeah, there is already a decent amount of overlap. I assume that will hold true with the 3rd site. The main problem is people forgetting to switch sites. The guy who came and reprogrammed all our radios when we rebanded said he could set our radios to switch automatically right now but he didn't feel comfortable doing it. Said something about it getting into an area where the coverage was equal and it would just constantly switch sites and you couldn't talk on the radio. That's why some type of switch is needed in dispatch. He also said that he could patch together two radios in dispatch and get it to work that way but it wasn't ideal.

Thanks a bunch for answering all my questions. I really appreciate it.