Java program to decode DMR

[IanWraith]

Hi Folks

DMRDecode build 61 is now available for download from the usual place ..

DMRDecode Download

Big new feature in this build is that it allows you to select your audio source from within the program. In addition if you save settings this build saves your audio source choice and then uses it when the program is restarted automatically.

Many thanks to Andy who originally contributed the code for this to Taxi MDT Decoder but which I have now ported over to DMRDecode.

Regards

Ian

 

[Forts]

Thanks Ian! That'll be a handy option to have....

 

[jeremym70]

DMR Decode issue

Hello DMR Decoder experts,
I have tried several times to get this program to work, but have had no luck. I have numerous MotoTrbo repeaters in the Portland, Oregon area to test on and have tried them all. I am using a Uniden 245 that has a discriminator tap fed into the line input on a Dell D530 laptop. This setup works fine with Trunk88, Unitrunker, etc.
I have tried the invert option, adjusted the input line level settings on the sound card. I get the half scale green bar on the bottom most of the time and the screen scrolls with data, however I get the No Sync message on the bottom and nothing appears in the Color Code or Channel Box. What data I see is included in the attachment. I have checked and unchecked the invert, capture and debug options as well but not sure how I should have those set.
Can anyone help?
Thank you,
Jeremy

 

[IanWraith]

Hi Folks
Just a quick post before I call it a day as its late here.

A bug has been found which means DMRDecode displays an error whenever you select a Virtual Audio Cable from the new sound source selection method. I am looking into it and all being well will have a new build out next week.

Regards

Ian

P.S Could anyone help Jeremy and his problems in the post above.

 

[IanWraith]

Hello All

I have just uploaded DMRDecode build 64 to the usual place ..

DMRDecode Download

This build fixes the audio selection source bug. In addition the capture and debug options are for now now disabled due to the confusion they were causing.

Regards

Ian

 

[nd5y]

Is this version supposed to decode audio?

 

[Forts]

No.

 

[mtindor]

Is this version supposed to decode audio?

Where are people hearing this? I've never seen a mention of it directly from Ian. And, the first guy who suggested it then later made a post suggestive of somebody having sent him a copy of DMRDecode with decoding abilities, but when prompted he would not confirm that was the case.

Mike

 

[Forts]

You got me. DMRDecode is strictly data display, ala Trunk88 and UniTrunker. For audio decoding you would have to take a look at DSD.

 

[molay]

DMRDecode can output voice packets to a listen TCP port so a third app can play actual voice. Maybe someone can modify dsd to accept these data, or maybe dsdauthor can add these as a feature in next release.

https://github.com/IanWraith/DMRDecode/wiki/Networking

 

[mikewazowski]

I've run DMRDecode and DSD concurrently on the same signal. Works easy enough.

 

[jeremym70]

Bump, help?

Hello DMR Decoder experts,
I have tried several times to get this program to work, but have had no luck. I have numerous MotoTrbo repeaters in the Portland, Oregon area to test on and have tried them all. I am using a Uniden 245 that has a discriminator tap fed into the line input on a Dell D530 laptop. This setup works fine with Trunk88, Unitrunker, etc.
I have tried the invert option, adjusted the input line level settings on the sound card. I get the half scale green bar on the bottom most of the time and the screen scrolls with data, however I get the No Sync message on the bottom and nothing appears in the Color Code or Channel Box. What data I see is included in the attachment. I have checked and unchecked the invert, capture and debug options as well but not sure how I should have those set.
Can anyone help?
Thank you,
Jeremy

 

[Forts]

How is your tap setup? Many times taps that work well with older technology (3600 baud trunking etc) do not work well, or at all, with more complex signals like DMR. Are you using a voltage divider with a cap and resistors?

 

[IanWraith]

Hello
Looking at your screenshot where a sync sequence but nothing else is being acquired the problem has to be a distorted DMR waveform. This is usually for one of two reasons ..

1) The signal you are monitoring is amazingly strong and is overloading your receiver.

2) There is some kind of a problem with your discriminator tap. I have come across a couple of users with similar problems in the past. Looking at their waveforms they appear to have what I can only describe as a partial discriminator output. It looks as though it is partially being processed somehow. As Forts said this might work with 3600 baud but isn't good enough for 4800 baud signals like DMR,

Also one last thing. You are monitoring the base output side of a DMR repeater aren't you ? DMRDecode won't work with simplex or mobile input sides of DMR signals.

Sorry I can't help more.

Regards

Ian

 

[sanjurjo]

I know that dmrdecode can identify when privacy is in use.

But is it possible to differentiate between systems using Enhaced privacy from those using Basic privacy?

Given the differences in encryption so publicly known: basic "static keys" vs Enhaced "rolling key" (alledged RC4 40bit key plus IV) should be differences between the two in signalling data, or am I wrong?

 

[Forts]

I would imagine the info is there somewhere, it just hasn't really been explored yet. In the case of Enhanced Privacy there should be something indicating which key is in use too, since you can have multiple keys. With Basic maybe not so much. Since you are only allowed one key it might be presumed that the other radios are set the same, so there is no need to transmit which key is in use.

 

[IanWraith]

Hi All

My suspicion is that the secrets of the encryption settings lay in the mysterious PI Header. Understand that and we are getting somewhere.

Ian

 

[riveter]

Bit off the current topic, but from previous reads of this thread I hear you're eager for logs of things not currently understood/supported.

Attached is the DMRDecode(b61) complete log of me attempting to send another radio a text message reading "Test message." The message was not delivered, as the destination radio was off. Right at the end as I got the negative-completion beep, the transmission was interrupted by a voice call at 10:08:09 (included in the log). That may have usurped my data transmission (we're locked to one slot on one repeater), so this might not be entirely complete, but I figure it's close enough. Not much in the way of DMR data related stuff here, so I hope this helps.

 

[inigo88]

Bit off the current topic, but from previous reads of this thread I hear you're eager for logs of things not currently understood/supported.

Attached is the DMRDecode(b61) complete log of me attempting to send another radio a text message reading "Test message." The message was not delivered, as the destination radio was off. Right at the end as I got the negative-completion beep, the transmission was interrupted by a voice call at 10:08:09 (included in the log). That may have usurped my data transmission (we're locked to one slot on one repeater), so this might not be entirely complete, but I figure it's close enough. Not much in the way of DMR data related stuff here, so I hope this helps.

WOW this is fantastic! I believe these are the relevant frames:

10:07:56 PM DMR Data Frame
CACH : TACT  Ch 1 Continuation fragment of LC 
[b]Slot Type : Colour Code 1 Rate ¾ Data Continuation
0010011100111011000100100110011100010010001111000010110100000010111100111101001001111001110100101011010001000010111101100010001011110010101100100010001110011011001001110100101100100111010111100010[/b]
10:07:56 PM DMR Data Frame
CACH : TACT  AT=1 Ch 2 Last fragment of LC 
Slot Type : Colour Code 1 Idle
10:07:56 PM DMR Data Frame
CACH : TACT  Ch 1 First fragment of LC 
[b]Slot Type : Colour Code 1 Rate ¾ Data Continuation
0010100000100010001000100010001000100010111100111111111000110010001000100010001000100010111001000000101010100010001000100010001000100010000000111000110111110010001000100010001000100010100111000011[/b]
10:07:56 PM DMR Data Frame
CACH : TACT  AT=1 Ch 2 Continuation fragment of LC 
Slot Type : Colour Code 1 Idle
10:07:56 PM DMR Data Frame
CACH : TACT  AT=1 Ch 2 Continuation fragment of LC 
Slot Type : Colour Code 1 Idle
10:07:56 PM DMR Data Frame
CACH : TACT  Ch 1 Continuation fragment of LC 
Slot Type : Colour Code 1 Terminator with LC
[b]Terminator Data Link Control PDU
Destination Logical Link ID : 50 Source Logical Link ID : 27[/b]

And it tries to resend later on:

[b]CACH : TACT  Ch 1 Continuation fragment of LC 
Slot Type : Colour Code 1 Rate ¾ Data Continuation
0010100000100010001000100010001000100010111100111111111000110010001000100010001000100010111001000000101010100010001000100010001000100010000000111000110111110010001000100010001000100010100111000011[/b]
...
[b]Terminator Data Link Control PDU
Destination Logical Link ID : 50 Source Logical Link ID : 27[/b]

And again here:

[b]CACH : TACT  Ch 1 Continuation fragment of LC 
Slot Type : Colour Code 1 Rate ¾ Data Continuation
0010000101111011001000101111101100010010111110100010110111111101001011101101001011110011110100100010111001111110111111110111001011110110001000100010010010110010001011111111101100100110001011100010[/b]
10:08:06 PM DMR Data Frame
CACH : TACT  AT=1 Ch 2 Last fragment of LC 
Slot Type : Colour Code 1 Idle
10:08:06 PM DMR Data Frame
[b]CACH : TACT  Ch 1 First fragment of LC 
Slot Type : Colour Code 1 Rate ¾ Data Continuation
0010011100111011000100100110011100010010001111000010110100000010111100111101001001111001110100101011010001000010111101100010001011110010101100100010001110011011001001110100101100100111010111100010[/b]
10:08:06 PM DMR Data Frame
CACH : TACT  AT=1 Ch 2 Continuation fragment of LC 
Slot Type : Colour Code 1 Idle
10:08:06 PM DMR Data Frame
[b]CACH : TACT  Ch 1 Continuation fragment of LC 
Slot Type : Colour Code 1 Rate ¾ Data Continuation
0010100000100010001000100010001000100010111100111111111000110010001000100010001000100010111001000000101010100010001000100010001000100010000000111000110111110010001000100010001000100010100111000011[/b]
10:08:06 PM DMR Data Frame
CACH : TACT  AT=1 Ch 2 Last fragment of LC 
Slot Type : Colour Code 1 Idle
10:08:06 PM Short LC : Act_Updt - Individual data activity on BS time slot 1 Hashed Addr 158 : No activity on BS time slot 2
10:08:06 PM DMR Data Frame
CACH : TACT  Ch 1 First fragment of LC 
Slot Type : Colour Code 1 Terminator with LC
[b]Terminator Data Link Control PDU
Destination Logical Link ID : 50 Source Logical Link ID : 27[/b]

I tried running the binary into some standard bin to ASCII calculators hoping to get lucky, but no luck. Will double check the 3/4 data PDU in the ETSI standard and see if I'm missing anything obvious...

There are also some embedded short LC's I've never seen, and I'm not familiar with those Short LC Act_Updt's either. What type of system is this?

 

[IanWraith]

Hello All
My thanks to dpcain for that fascinating info. This is more than a little interesting because I have been working on text decoding but in the log I have been sent the data is sent (as Unicode) in 1/2 rate data packets. Here were appear to be seeing them in 3/4 rate packets.

Note that you won't be able to pick out any ASCII in 3/4 packets as it is trellis encoded. I really need to make time to get 3/4 rate data decoding in DMRDecode.

Thanks again.

Ian