Batboard

The local fire dept uses an analog Type II 800 MHz system and when the officer requests a knox box key it is transmitted as a DTMF sequence over the talkgroup that they are operating on.

We dont have them at my home department so I am unfamilar with how these things work.

Here is my question: How does the actual box recieve the key? It seems unlikely that the box is able to recieve the key from the fire talkgroup because of the simple fact that every box would have to be capable of recieving on the trunk system.

Just wondering,

Mike

Good question.

The Knox boxes that we use in this city have a key that accesses them. We have a different key for each district and the chiefs have keys that open them all. Inside the box there is a pass key or master key to the premesis. I have seen Knox boxes that use a combination to open the box rather than a key. Perhaps your city uses that type of Knox box. Assuming so.............

My best guess would be that the boxes all have individual combinations, to prevent one combination from getting "loose" and having to take the time to reset the combination of each box. I would guess the dispatcher has a master list of all the combinations for each Knox box at each address, or perhaps has them programmed into the dispatch console. When the unit on the scene needs to access the Knox box for a key then the dispatcher sends the combination over the air to the portable unit, and it simply displays on the screen. Punch in the combination, and whamo, you have access to the pass key.

Again, all just a guess; but I think that would explain what you are hearing.

Any other ideas?

-Justin

Most knox box installs within firetrucks have a simple audio tap from the truck's radio. It has it's own decoder built in.

This the type of box?

tpg

that's what ours has. DTMF over LTR trunked system, fed directly into Knox box. beep boop boop beep beep beep - :click:

The Pager Geek wrote:Most knox box installs within firetrucks have a simple audio tap from the truck's radio. It has it's own decoder built in.

This the type of box?

tpg

This might be the case. If so, then that way each engine or ladder would have a box on board with the keys, floor plans, etc for buildings in its first due area.

That would make more sense than what I had originally thought which was that the box is physically on the building in question. That would mean that each box would have to be able to recieve on the TRS which didnt seem quite right

Mike

TPG has it, it's just a simple audio tap. When the correct DTMF sequence is issued the box unlocks and the officer can remove the key from the truck. That key will open a lockbox on the building which will have keys, access codes, maps and contact info depending on the owner of the building and what size knox box he bought. These systems can differ widely depending on what the agency spec's out.

When you purchase a Knox Box you need to specify what FD and they will send it already keyed to that agencies system.

The Knox Box is just a key box on the building with master keys in it that takes a property key specific to the fire department to open the box. Most departments secure the Knox Box Key in some type of lock box on the truck. Knox makes a high security system that interfaces the lock box on the truck to the radio and requires the dispatcher to send a special set of tones to the box to unlock it. This allows them to track when the key is taken off the truck.

http://www.knoxbox.com/store/knoxsystem ... N=88726871

http://www.knoxbox.com/store/search-res ... N=88726871

Fuel4300 wrote:This might be the case. If so, then that way each engine or ladder would have a box on board with the keys, floor plans, etc for buildings in its first due area.

That would make more sense than what I had originally thought which was that the box is physically on the building in question. That would mean that each box would have to be able to recieve on the TRS which didnt seem quite right

No, the box on board the truck only retains a key to the boxes on the buildings. They way you describe it they'd need to have a uhaul full of file cabinets in the small box.

The DTMF must be programmed into the dispatch console because it is definitely not being dialed on a hot keypad from the sound of it.

No, the box on board the truck only retains a key to the boxes on the buildings. They way you describe it they'd need to have a uhaul full of file cabinets in the small box.

Haha... yea... didnt think that one through.

It all makes sense now.

Thank you all,
Mike

Fuel4300 wrote:The DTMF must be programmed into the dispatch console because it is definitely not being dialed on a hot keypad from the sound of it.

I'm assuming knox provides an interface to your system as the tones aren't really DTMF tones, they are slightly off by a few hz. I've never seen that side of the system.

i was unaware that those are nonstandard DTMF tones.

A good idea, but I'm not a big fan of the Knox company (or aleast some people within the company). A few years back we had a problem with them trying to get the city/planning dept. to put forth an ordinance that would force building owner to us Knox boxs on many buildings. It didn't make it very far thankfully.

I don't really have a problem with the idea in general and it works great for some buildings, but for others it not something that is needed and/or acceptable.

Why not? If you're building a new building, what's an extra $500 for a box that guarantees that the FD doesn't break my door down or break out a window on a false fire alarm caused by the city water pressure fluctuating? Their response would typically be within 5-10 minutes. Mine, could be longer, especially if I got stuck in traffic. I know several cities that require it on new commercial buildings. Now going back to the existing buildings would cause trouble.

When I installed alarm systems, I used to wire up the tamper switches on them. So if a crooked FF or PO wanted to peruse your building without cause, someone would know that it was happening.

One other thing about the Knox Box system that has'nt been mentioned here. Some units have a set of "Fobs" that, when applied to the proper spot on the key retention box in the truck, will allow access without the code. This is used in the event that the radio cannot recieve a signal to unlock the key. Usually, these are given to the chief or the officer of the day, but are ONLY to be used if the box cannot be opened in the normal fashion. There are 2 or 3 of them and each is a different color.

The system it's self is pretty ingenious as the key is actually inserted into a regular lock cylinder (like on a door lock) and then turned to lock it in place. If you try to remove it, you break the key making it ineffective. Also, you cannot gain access to the inners of the key retention box unless the key is removed, which is just another security step to insure that no unauthorized personell access the system or it's inner workings.

Lastly, both the key retention box and the store key boxes are virtually indestructable. You would REALLY need to do some heavy drilling to try and get into either of the boxes. Here's a couple of pics of the master key secure box and the building box. The master box is a newer style which allows direct access with a keypad punch.





Here is a pic of the style that uses the radio signal and also has "fob" access. The fob would be placed near the little silver button on the bottom right of the unit.

Chuck's right those things are "tank proof" we use them on our department, we have the sentralok verison on our medics and engines, in order to gain access to the key we must radio dispatch, tell them what truck you are on and your FD unit # and then they will send out the dtmf for that truck and presto there is your key, each truck has it's own dtmf combunation, no one box is the same. as chuck also said if the unit does not resopnd to the dtmf/tones you have the "fobs" to override the system. it does have the three keys yellow=programing reset (if the box errors out 4 times in 10 min it locks its self you need the yellow key to reset) black=lockout (so if your truck is out of service box is inoperatable dtmf will not unlock the key until reset with the yellow key )
silver=(knox key override), one thing to check if you box does not respond to the dtmf/tones check to make sure the radio volume is turned up, we had the issue of the key not releaceing, after a call to the knox company we found that the box picks up the dtmf/tones from the discrimator side of the radio, and if the volume is to low the box can't recieve the unlock code, as for the special set of tones, they are standard dtmf and can be set off of a hot keypad if, you know the proper number 6-12 digits, speed of the the dtmf, I would not give that information out due to the fact that you are losing the security and the tracking of the key, and if some one was to set those dtmf and use the key it would open your department up to a whole mess of things, ours is installed into the dispatch console so that the radio traffic and dtmf is recorded on the 911 tapes. knox does make a stand alone keypad system that can be placed in dispatch in case there is no room in the console for the dtmf/tones.

Jeffrey

My station has a more "trusting" approach, I guess. Each truck has a small keysafe on it where the Knox key is kept. The keysafe is opened with a standard combination lock... looks like this:



When the unit is out of service, the key is kept in a lock box (opened via combination lock) in the control room at the station.