MDT Question

[dgoodson]

Sorry if this is the wrong forum... tell me where to go.

My PD/FD uses a plain old Moto type 2 analog 800MHz TRS. PD units, and fire engines are equipped with Mobile Data Terminals (computers). Do those MDT transmit and receive their data using the TRS "channels" or something else? is there any practical way to decode and display the data traffic being sent back and forth?

TIA

 

[RodStrong]

is there any practical way to decode and display the data traffic being sent back and forth?TIA

I sure hope there isn't. That would compromise some pretty important business and confidential information.

 

[davidp124]

dgoodson:

Our city/county 800 analog TRS is seperate from our MDC system. MDC system uses another set of 800 frequencies which are not trunked.

 

[garys]

Every system I've heard of uses either a separate dedicated frequency or cell phone air cards. It is illegal to decode MDT, MDC, MWS, MCT, or whatever an agency may call it, data.

Gary

 

[mtindor]

Sorry if this is the wrong forum... tell me where to go.

My PD/FD uses a plain old Moto type 2 analog 800MHz TRS. PD units, and fire engines are equipped with Mobile Data Terminals (computers). Do those MDT transmit and receive their data using the TRS "channels" or something else? is there any practical way to decode and display the data traffic being sent back and forth?

TIA

No practical way, and it would be illegal to do so... at least in the states. This may even be a prohibited topic of discussion here on RR, so proceed at your own risk.

Mike

 

[studgeman]

To answer the question.....

on the 800 Trunk? Maybe, maybe not. Could be on other frequencies, could be on Cell cards also. As far as decoding it, there is a significant process you would have to go through for any of it. It really isnt worth describing the process becuase there are whole books on it. So unless you are a software and electrical engineer with alot of time on your hands, its not going to happen. There is no software out there to decode any of the current MDT systems.

It is a reasonable question though.

 

[br0adband]

I think it should be clarified with respect to legality here in the US:

It is not illegal to receive the transmissions that are on licensed frequencies - if that was the case, the MDT transmissions would be in a "protected" area (like in a specific band segment) that scanners would simply not tune in, aka the cellular band. Since the MDT transmissions happen in the 851 to 869 band, which is monitorable, you can listen to that traffic as much as you want.

What is illegal, however, would be using equipment or software which would decrypt the MDT transmissions since it's a very safe bet that all public safety systems are smart enough to use encryption on that traffic now.

It's entirely too easy for people to spit out "oh it's illegal to monitor that" when that's simply not the case. You can listen to MDT traffic, but since it's a digital stream, and it's encrypted too, you're not actually going to get much if any useful information from it, obviously.

ps
My 300th post... w00t!

 

[mtindor]

It's entirely too easy for people to spit out "oh it's illegal to monitor that" when that's simply not the case. You can listen to MDT traffic, but since it's a digital stream, and it's encrypted too, you're not actually going to get much if any useful information from it, obviously.

ps
My 300th post... w00t!

The question remains... why would anybody want to tune to it if they can't decode it? Do you routinely sit idle on MDT frequencies listening to the encrypted data?

Mike

 

[br0adband]

No particular reason I suppose, but even so it's nice to clarify and make it very clear what is and what isn't illegal.

Hell, people do "illegal" things all the time, so what's the point? Ever find yourself driving 27 in a 25 MPH zone? That sort of thing? Might not seem like such a big deal but it is illegal and you are "breakin' the law" when you do it.

It's too easy for people to just say "Hey, that's illegal" without backing it up, then others read the comment and automagically assume that something is illegal and never question the comment again.

Knowledge isn't power, far from it. Applied knowledge is.

 

[gmclam]

MDT or MCT

My PD/FD uses a plain old Moto type 2 analog 800MHz TRS. PD units, and fire engines are equipped with Mobile Data Terminals (computers). Do those MDT transmit and receive their data using the TRS "channels" or something else?

I've never seen these type of transmissions on a TRS, there is a dedicated frequency. What I've also experienced is that when the unit is called an "MDT", the remotes do not transmit back. When the unit is called an "MCT", etc; the remotes do transmit back.

is there any practical way to decode and display the data traffic being sent back and forth?

When they first started this in my area, circa 1975, all you needed was a receiver, a modem and a dumb terminal. I forget now if they were using 1200 baud or 9600 baud. Over the years the "connections" between the remote units and the central computer(s) has become secured. The analogy would be like comparing old days when you could log onto a public BBS vs current logging in to an ISP.

The direct answer to your question totally depends on the specific system you're trying to monitor and how sophistacted they are. Here in my area I hear lots of voice traffic of officers not being able to log onto the system. If authorized users are having troubles, that seems to be an indicator of the "difficulty" or practicality for the rest of us.

 

[AZScanner]

I've done considerable research on the subject. First, a disclaimer. Monitoring (aka decoding the data from) these systems is not technically illegal unless they are encrypted (they usually are these days) but it's still a fine way to get yourself in so much trouble that you'll wish you never attempted it. Don't be stupid - if you do then you deserve the legal reaming you will get. Look up Bill Cheek on google and read up. What he did was not technically illegal either but that didn't stop the government from ruining his life.

Now, having said that, I'll fill you in.

It's doubtful, but if you live in an area that's using the old MDC4800 protocol then you're in luck - do a google search for mdtmon or mdt monitor - it was a great little VB app that let you monitor MDT traffic. As for legality it's a gray area since all the application did was decode the protocol - there was no encryption on MDT systems in those days. Some agencies still use this protocol but many have upgraded since then.

More likely, the agency you want to monitor will be using the RD/LAP protocol. Sorry to say but you're out of luck if so. There's no software written to decode it so you'd have to figure that out yourself. And if it's encrypted then it will do you no good unless you also have the skills required to crack DES encryption. It's been done, but it took a room full of geniuses to do it.

Bottom line is this. It's technically possible to do, even today, but you won't find anyone offering software that does it unless they are either completely insane or reside in a country with no extradition treaty. Even then, such a program would be infringement on dozens of patents and copyrights held by Motorola (and they have so many lawyers on staff that they could literally sue you off the planet). It's just not worth attempting... publicly.

-AZ