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N_Jay
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NCSHP311 said:
I call BS.
How Does an MDT work and can it be scanned?
- Thread starter dimab
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I call BS.
Al42
Member
Since Texas can only legislate what happens in Texas, and since any signals generated in Texas travel outside Texas, the law is pretty useless (not to mention illegal).rfmobile said:
hcsd35-32
Member
I find that very hard to believe. You would have to have one powerful computer to break any kind of up to date encryption. Definitely sounds like BS.NCSHP311 said:
kgasso
Member
JerryNone said:
I have to respectfully disagree with this generalization; I can sit all day and listen to the data bursts on our local PD's VHF MDC system repeater and not break the law here. If it were unencrypted and I were to log/view the data, from my understanding I'd still be legal as long as I didn't use any data obtained in an illegal manner.
However, I think the line is crossed when I start to decrypt scrambled/encrypted comms (DES, IPSEC, etc.) or if I listen on frequencies where I'm not allowed to monitor (cellular).
(but what do I know, I'm not a lawyer
)Ok so after 4 years in college i may have learned something. Most laws are written to say what you cannot do, though in message board posts it is usualy easier to say what you can do. Consider this a summary.
According to Federal regulations, and there are a host of them, interception and decoding of a radio transmission is legal. There are only 3 specific exceptions to this rule, 1. Cellphones, 2. Cordless Phones, 3. Paging transmissions. It is legal to decode a digital signal back into its origional form, as long as that digital transmission is not encrypted. Under this defination encryption is a secondary process subsequent to first encoding. For an analog encrytion method, encryption would have to be applied after the voice is converted to an electrical signal. For digital you would take your digital bit stream and encrypt that, then modulate your RF. Propritary modulation schemes or methods of encoding does not mean encryption. ie. ProVoice and DataRadio are propritary but not necessarily encrypted. If they are not encrypted, they are fair game. Remember, we live in the United States, not China!
This is the Federal answer to this question, your state or locality may have other laws which govern this topic. Aparently Texas is one of those states, New York is questionable, but aren't they always?
Oh someone asked this question a few posts back. The top speed on a conventional channel 20kHz bandwidth is 96k, its a Motorola product. Top speed on a narrowband channel 12kHz is about 36K and that is a DataRadio product. DC has a Flarion system running on an experimental 700MHz license. if i remember correctly it uses 50MHz and gives about T-1 speeds and bursts significantly higher.
According to Federal regulations, and there are a host of them, interception and decoding of a radio transmission is legal. There are only 3 specific exceptions to this rule, 1. Cellphones, 2. Cordless Phones, 3. Paging transmissions. It is legal to decode a digital signal back into its origional form, as long as that digital transmission is not encrypted. Under this defination encryption is a secondary process subsequent to first encoding. For an analog encrytion method, encryption would have to be applied after the voice is converted to an electrical signal. For digital you would take your digital bit stream and encrypt that, then modulate your RF. Propritary modulation schemes or methods of encoding does not mean encryption. ie. ProVoice and DataRadio are propritary but not necessarily encrypted. If they are not encrypted, they are fair game. Remember, we live in the United States, not China!
This is the Federal answer to this question, your state or locality may have other laws which govern this topic. Aparently Texas is one of those states, New York is questionable, but aren't they always?
Oh someone asked this question a few posts back. The top speed on a conventional channel 20kHz bandwidth is 96k, its a Motorola product. Top speed on a narrowband channel 12kHz is about 36K and that is a DataRadio product. DC has a Flarion system running on an experimental 700MHz license. if i remember correctly it uses 50MHz and gives about T-1 speeds and bursts significantly higher.
hcsd35-32 said:
Believe it if you want to or not I have seen the program work myself and it decyphers encryped messages!
wozz
Member
NCSHP311 said:
What kind of encryption?
refering to my earlier post my friend has this software and showed it to me one day not sure what type of encryption I have emailed him for the link to the download he used to get the program.
kgasso
Member
Sounds like the "MDT Monitor" app. If I remember correctly... and if that's what this is, that doesn't do decryption, it just decodes the data bursts and messages (message id to text/etc.)
PanJurekMrJerry
Member
What? Somebody has enough computing power to decipher the alogrithem?
N
N_Jay
Guest
JerryNone said:
Deciphering the channel coding algorithm is one thing, decrypting an encoded stream is quite another.
radio10-8
Member
MDT/MDC by Software
Intergraph CAD (imobile) requires that you 1st have the software installed, and your laptop have an IP address the system will recognize to start, OK let's say you have a laptop with imobile installed and lets say you have it connected to either the Sprint/Verizon who ever cellular network or you have the 800mhz radio connection. You will try to logon but you will need a unit ID (Radio callsign) and proper badge or ID (User ID) to logon. Without those two you have nothing. dont forget the IP address, so really you need three things. Other than reading the "I.M's" between officers or dispacthers there is really nothing good. Once in a while sensitive calls are dispatched via MDC otherwise most agencies still voice the call on the radio. I know of people that have bought used MDT's on ebay and were stopped from doing anything because they had no logon info and the IP address had been removed from the system. Other than powering up the logon page and having a police logo showing it was nothing.
Intergraph CAD (imobile) requires that you 1st have the software installed, and your laptop have an IP address the system will recognize to start, OK let's say you have a laptop with imobile installed and lets say you have it connected to either the Sprint/Verizon who ever cellular network or you have the 800mhz radio connection. You will try to logon but you will need a unit ID (Radio callsign) and proper badge or ID (User ID) to logon. Without those two you have nothing. dont forget the IP address, so really you need three things. Other than reading the "I.M's" between officers or dispacthers there is really nothing good. Once in a while sensitive calls are dispatched via MDC otherwise most agencies still voice the call on the radio. I know of people that have bought used MDT's on ebay and were stopped from doing anything because they had no logon info and the IP address had been removed from the system. Other than powering up the logon page and having a police logo showing it was nothing.
Al42
Member
To be fair, New York regulates where, and under what conditions, you can listen. It doesn't regulate what you can listen to.studgeman said:
Lets leave the whole legality issue of decyphering encryption out of this thread. We all know where it goes. I'd prefer not to read another post about someone reminding someone about what's legal and what isn't. We KNOW already!
The primary reason many MDTs aren't able to be monitored (provided they aren't using a commercial wireless carrier) is because of the private protocol used for data communication. Most of these private networks (e.g., RD-LAP) are not encrypted also. Since laws don't generally stop people from developing software to crack or decode something the only issue is getting someone with the coding skills to reverse engineer the protocols used for MDT/MDC traffic. As mentioned, MDC-4800 was done but today's data protocols used for mobile data are a hell of a lot more sophisticated. An individual, many years ago, attempted to start coding software that decoded RD-LAP but bowed out due to legal folks breathing down their neck.
So, really, it's not impossible to do, it just takes a LOT of time, and people generally with the skills to code and crack the protocols don't have the time to get into it.
Btw, Joe Schmoe isn't just going to up and start a movement to crack/decode whatever protocol because he got an itch to do it from some forum so please lay off the whole what's not legal thing. It's legal to talk about it, or talk about ways of doing it, so give it a rest. No one here will censor anyone who does.
-Wayne
The primary reason many MDTs aren't able to be monitored (provided they aren't using a commercial wireless carrier) is because of the private protocol used for data communication. Most of these private networks (e.g., RD-LAP) are not encrypted also. Since laws don't generally stop people from developing software to crack or decode something the only issue is getting someone with the coding skills to reverse engineer the protocols used for MDT/MDC traffic. As mentioned, MDC-4800 was done but today's data protocols used for mobile data are a hell of a lot more sophisticated. An individual, many years ago, attempted to start coding software that decoded RD-LAP but bowed out due to legal folks breathing down their neck.
So, really, it's not impossible to do, it just takes a LOT of time, and people generally with the skills to code and crack the protocols don't have the time to get into it.
Btw, Joe Schmoe isn't just going to up and start a movement to crack/decode whatever protocol because he got an itch to do it from some forum so please lay off the whole what's not legal thing. It's legal to talk about it, or talk about ways of doing it, so give it a rest. No one here will censor anyone who does.
-Wayne
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tfr
Member
The M.D.T.s here in Estonia are home-brewn and actually pretty nice. This is how they look in a car:
There's a 7" LCD display mounted on the dash and then a wireless (IR) keyboard. The machine is a specially designed PC running on the Transmeta processor - according to the guys who designed the system, the only i386 processor available today that gets away with a heat sink and does not require a fan. In addition to that there's no hard drive - the whole system is pre-loaded on a 1GB CF card - so if there's a software upgrade, the card is just replaced with one containing a newer version. Altogether - no moving parts, which is good for a mobile application.
The system is running a special application on top of Linux. The primary application is ofcourse the query tool for running licenseplate/DL queries, but there's also a map application that is useful for finding a quickest route to the next call.
The system also includes a GPS module, which shows the current location of the vehicle in the mapping software, and also reports the coordinates every once in a while (about every 30 seconds I've understood) to the dispatch center so they have a good overview of where their units are located and which one is closest to the current call. Data exchange is done using GPRS over a public GSM network - there's a PCMCIA GSM card in the PC. The whole system uses a specially designed, low overhead data protocol.
There's a 7" LCD display mounted on the dash and then a wireless (IR) keyboard. The machine is a specially designed PC running on the Transmeta processor - according to the guys who designed the system, the only i386 processor available today that gets away with a heat sink and does not require a fan. In addition to that there's no hard drive - the whole system is pre-loaded on a 1GB CF card - so if there's a software upgrade, the card is just replaced with one containing a newer version. Altogether - no moving parts, which is good for a mobile application.
The system is running a special application on top of Linux. The primary application is ofcourse the query tool for running licenseplate/DL queries, but there's also a map application that is useful for finding a quickest route to the next call.
The system also includes a GPS module, which shows the current location of the vehicle in the mapping software, and also reports the coordinates every once in a while (about every 30 seconds I've understood) to the dispatch center so they have a good overview of where their units are located and which one is closest to the current call. Data exchange is done using GPRS over a public GSM network - there's a PCMCIA GSM card in the PC. The whole system uses a specially designed, low overhead data protocol.
MacombMonitor
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I hope they disabled the air-bag on the passenger's side!
tfr
Member
MacombMonitor said:I hope they disabled the air-bag on the passenger's side!
Yep, that's what they've done in these cases - the exact location of the LCD is varying by model. Government purchases, including police vehicles, have to be made through a public auction and go to the lowest bidder - to ensure that they get a different model every time they need some new cars.
I wonder what type of camera mount that is I need one of those......
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