Major trunking system malfunction

[bnglbill]

I was talking to an old friend yesterday from my days as an armed security officer. He brought up a situation that we had once that I had totally forgotten about and I want to share it with you all.

We were using Motorola radios on a business 800 mhz. trunked system and one day, we found ourselves on the same frequency as all other businesses on the system. It seems that something failed on the tower causing the system to act as a conventional radio system, What a major blunder!! We were all stepping on each other and trying to sort out what was going on, there must have been at least 10 different businesses on there.

Anyway, I was wondering if any of you all know what could have failed at the tower that caused this to happen and do you think that this could happen on a public safety system? Could you imagine if all of the districts in a county, city or state just ended up all on the same frequency, what a mess that would be.

 

[N_Jay]

I was talking to an old friend yesterday from my days as an armed security officer. He brought up a situation that we had once that I had totally forgotten about and I want to share it with you all.

We were using Motorola radios on a business 800 mhz. trunked system and one day, we found ourselves on the same frequency as all other businesses on the system. It seems that something failed on the tower causing the system to act as a conventional radio system, What a major blunder!! We were all stepping on each other and trying to sort out what was going on, there must have been at least 10 different businesses on there.

Anyway, I was wondering if any of you all know what could have failed at the tower that caused this to happen and do you think that this could happen on a public safety system? Could you imagine if all of the districts in a county, city or state just ended up all on the same frequency, what a mess that would be.

It's called failsoft, and iot is a whole lot better than no communications.

Something in the controller failed.

Public safety systems typically have critical equipment like the controller designed in a redundant configuration.

 

[akardam]

Within my limited experience with trunking systems, it sounds like the controller went into failsoft. In that case, as far as I know, most every user of the system *would* end up on one or two conventional channels. It depends on the size of the system, the number of sites, freqs, etc, but if it was a small business system it is likely that it wasn't programmed up for more than a couple failsoft frequencies.

Could it happen to a public safety system? It's possible, but most public safety systems are monitored by their radio techs 24/7, and would probably be able to cut over to backup controllers, etc. Plus, their failsoft plan would (should!) be a little more robust.

 

[INDY72]

Could it happen? Yes
Does it happen? It used to be pretty frequent for some systems.

On the Motorola systems when the controller fails, or something catastrophic should happen.. Each fleet in the system is set to go to a specific repeater/repeaters in failsoft mode,.. and it resorts to conventional mode. Though some systems are now designed with site controllers that keep each repeater trunking unless a system wide failure is to happen (God Forbid). On the older EDACS systems, trunking would still occur, but the specail features that the system controller had would be lost until the bug was fixed.... Not sure how this is set up on the newer EDACS.

I have no clue as to MPT systems, OpenSky, or TETRA.

On LTR Standard. each fleet switches to its home repeater and goes to conventional mode.....

I am sure its the same for LTR MultiNet.

Passport LTR I have to assume also functions as fully conventional with fleets going to a home repeater in this eventuallity.

 

[Raccon]

TETRA can offer a feature called "fall-back mode," the most basic service provided then is group communication. Some vendors offer more advanced features like individual calls or even SDS (text messaging).
Note that fall-back is an optional feature, i.e. the vendors must not provide it (some may not even have implemented it into their system).

 

[pepperpot]

Failsoft

Something like this happened on a limited basis on our county Motorola Astro system this morning after yesterday's snowstorm. Man, those county bus drivers were not happy in the least to have the plow drivers on the same freq. Shouting and screaming.
Problem was fixed rather quickly.

 

[RolnCode3]

As my County's radio system ages (it's now about 10 years old), this is becoming more and more frequent.

Listed on the fleetmap is a failsoft frequency listed next to the tg info. It tells you specifically which frequency each talkgroup will default to. Each of the Sheriff dispatch channels get their own frequency. Some of the police departments get their own. Fire departments get their own.

All of the local government has to split up the remaining frequencies, and there are usually a bunch of agencies on one frequency at that point.

So, when the system goes down, I have in my scanner which talkgroup will be using which frequency.

It is a pain, but as long as you know what's happening, you can get around it. The constant static and beeping should be a clue, but someone ALWAYS asks "what's going on??". To which he usually gets about 3 replies.

 

[Grog]

When I monitored the Horry Co system (95-99) it would sometimes go into failsoft mode. Pretty funny to hear everyone on the same freq trying to figure out what happened

 

[fineshot1]

Failsoft

Most of the motorola trunking systems i have delt with have 2 controllers.
One being the primary and the other a backup. Once a failure occurs on the active controller the backup takes over control of the system. However sometimes if the system is very busy at the time of the failure it can take a few moments for the backup to actually kick in as the active controller and there are a few moments that the system goes into failsoft. Most of the users and sometimes the dispatchers will panic until they realize what just happened. As far as the robustness of a failsoft plan - that is limited by the number of talkgroups, the number of users, how busy the system is, and the number of channels in the trunking system and some other minor parameters.......dan

 

[Jay911]

I shudder to think of what the users of our system might do if the system went into failsoft. They don't use the channels we have now properly - we have a bunch of talkgroups common to all agencies, but the conventional "wisdom" is that we should patch those groups to our existing main talkgroups. I can't imagine what people would do if all three public safety services plus the other users of the trunk system (which I'm sure no one realizes is on our system) are all on one channel.

The system, in the time I've been using it, has never gone into failsoft. What's more likely with us (and much more frequent) is that it goes into "Site Trunking". There are six tower sites, and if the hardline link between one of the sites goes down, that site goes into Site Trunking mode. Generally, everyone using that site can still use it as a fully functional trunk radio system, but the site is not connected to the rest of the network. Think of that one like a school or office with computers all hooked into a network. Each office has all its computers hooked into their own patch panel, all going back to the main server in the computer room. If the cable from the patch panel in Office #3 to the server room is disconnected, the computers in Office #3 can communicate with one another, but the rest of the network is off limits to them.

 

[chrisjz]

Out of the radio business. Deleted...