BCD536HP not showing ENC on Phase-II encrypted talkgroups

[wm8s]

I'm monitoring TxWARN on the General Services site, so I'm getting Phase-II traffic (verified by the fact that I'm seeing PT0 and PT1 icons). I know that, for example, Fire talkgroups AC4 and AC6 are encrypted, but the 536 tries to play them, showing PT0 or PT1, as appropriate [I assume] and not ENC. I can Avoid them, of course.

Anyone else seeing this? Is Houston FD using an encryption that the 536 doesn't understand?

...R

 

[JamesO]

There are 2 different things to keep separated, Encryption and Scrambling.

I would be VERY surprised that Fire talk groups would be Encrypted, Scrambled maybe. Encryption would not likely be needed on Fire talk groups. Much less Scrambling, however, Scrambling is far cheaper and may even be a "standard" feature in some systems. Encryption brings additional cost and additional system management challenges.

Typical Encryption sounds a bit like white noise where scrambling sounds like chopped and inverted audio, something similar to listening to SSB.

I can confirm that the 536HP does not seem to be able to avoid/mute Scrambling.

 

[whooey]

Anyone have audio samples with the difference between enc and scrambled?

 

[JamesO]

This is Scrambled audio - Listening to Encrypted Police Frequency on a Radio Shack PRO 197 Digital Trunk Tracking Scanner - YouTube

42 seconds to the 1 minute mark.

Encryption is a constant and consistent white noise hiss sometimes with a light beep at the end of the conversation. The 536HP does not unmute the squelch for Encryption and you should see ENC displayed on Encrypted channels. It appears that the 536HP and probably the 436HP will stop on Scrambled comms and open the squelch.

People mix up Scrambling and Encryption all the time, two VERY different things. Even the person that posted the YouTube video said is was Encryption, which it is not.

Here is what DES Encryption sounds like - http://www.youtube.com/watch?v=5UKOToLA7-s

This talks about Analog, however, the same basic think happens with P25 or Analog.

What you hear on most P25 systems is voice Scrambling. Where you can kind of make out bits of the voice.

 

[fxdscon]

This is Scrambled audio - Listening to Encrypted Police Frequency on a Radio Shack PRO 197 Digital Trunk Tracking Scanner - YouTube

42 seconds to the 1 minute mark.

Encryption is a constant and consistent white noise hiss sometimes with a light beep at the end of the conversation. The 536HP does not unmute the squelch for Encryption and you should see ENC displayed on Encrypted channels. It appears that the 536HP and probably the 436HP will stop on Scrambled comms and open the squelch.

People mix up Scrambling and Encryption all the time, two VERY different things. Even the person that posted the YouTube video said is was Encryption, which it is not.

Here is what DES Encryption sounds like - Motorola Astro saber talking encryption - YouTube

This talks about Analog, however, the same basic think happens with P25 or Analog.

What you hear on most P25 systems is voice Scrambling. Where you can kind of make out bits of the voice.

Check the encryption sample here.... scroll down to section 2 and read the paragraph under the heading "AES and DES Encryption". Then click the link that starts that paragraph to listen to the sample.

W2SJW - Radio Sounds

.

 

[dtscho]

I'm monitoring TxWARN on the General Services site, so I'm getting Phase-II traffic (verified by the fact that I'm seeing PT0 and PT1 icons). I know that, for example, Fire talkgroups AC4 and AC6 are encrypted, but the 536 tries to play them, showing PT0 or PT1, as appropriate [I assume] and not ENC. I can Avoid them, of course.

Anyone else seeing this? Is Houston FD using an encryption that the 536 doesn't understand?

...R

Interesting...looks like another case of the 436/536 not muting encryption on Phase II talkgroups. It's not muting the encrypted MPD talkgroups (which are Phase II) on this system:

Washington, DC (Project 25) Trunking System, Washington, District of Columbia - Scanner Frequencies

It is muting the encrypted talkgroups (which are Phase I) on this system:

Stafford County Trunking System, Stafford, Virginia - Scanner Frequencies

Dave

 

[freqhopping]

I would be VERY surprised that Fire talk groups would be Encrypted, Scrambled maybe. Encryption would not likely be needed on Fire talk groups.

Why? Fairfax and Loudoun have encrypted channels for the fire marshals.





Right now there are active encrypted TDMA comms on the Loudoun Co, VA system. Not muted and no displayed indication of an encrypted channel other than my own alpha-tagging.

 

[JamesO]

Why? Fairfax and Loudoun have encrypted channels for the fire marshals.





Right now there are active encrypted TDMA comms on the Loudoun Co, VA system. Not muted and no displayed indication of an encrypted channel other than my own alpha-tagging.

Fire Marshall's are VERY different than a Fire Talk group. Fire Marshall's carry guns and have Law Enforcement authority.

I have not run into any Scrambling/Encryption yet on Fairfax, but maybe I have missed it??

 

[wm8s]

As I pointed out, this is a Phase-II TDMA system. And I said what I meant: These are encrypted talkgroups, not "scrambled" or anything else. Just because things are done one way in one part of the country does not mean they are done that way in every part of the country. All but a very few of Houston's police, fire, and EMS Phase-II TGs are full-time encrypted. For many jurisdictions, 100% of their TGs are encrypted: police, fire, all channels, all kinds, all the time.

Also, I can add another talkgroup on this system (RR #4563) to the list of ones the 536 tries to play even though they're encrypted: 30102 (DC11), plus 40031 (AA11), 40103 (AC5), and 40106 (AC8).

The scanner displays the Phase-II slot number instead of ENC, as expected.

 

[JamesO]

If it is really Phase II Encryted talk group, then there may be an issue with the firmware?

I just received my 536HP on Sat, only played with it for a while yesterday, I did see a few Encrypted talk groups pop up probably for the Uniformed Secret Service?? Did not program the system in, assume USS was not TDMA Phase II, I noticed it appeared to stop on the channel, ENC displayed, but the squelch did not open up.

I have seeming quite a bit of Scrambling here and there, it appears the Washington, DC Police is using Scrambling on most of their talk groups. But I am having the scanner stop and open the squelch on Scrambled comms.

The problem most people do not understand the difference between Encryption and Scrambling when it comes to public safety comms. I would geuss that Scrambling is more common than Encryption. Encryption and Scrambling makes inter agency and multual aid a bit tricky, it can be done, but it involves more management from the system admins.

 

[KevinC]

I'll 2nd this, it doesn't mute encryption on Phase 2 TDMA TG's, Phase 1 FDMA appears to mute.

 

[ofd8001]

It could depend upon the type of encryption used. "ADP" is a Motorola encryption method. It is used on the system I monitor.

When the scanner comes across a talkgroup that I know uses ADP, the ENC doesn't always show up. But if I hold on the talkgroup and then there is a transmission with ADP, the ENC does show.

(For those wondering how I know there's a transmission on an ADP talkgroup, the radio system has one of these patched to a UHF channel. I can listen on another scanner to that UHF frequency and know there's a transmission on the encrypted talkgroup).

 

[KevinC]

It could depend upon the type of encryption used. "ADP" is a Motorola encryption method. It is used on the system I monitor.

When the scanner comes across a talkgroup that I know uses ADP, the ENC doesn't always show up. But if I hold on the talkgroup and then there is a transmission with ADP, the ENC does show.

(For those wondering how I know there's a transmission on an ADP talkgroup, the radio system has one of these patched to a UHF channel. I can listen on another scanner to that UHF frequency and know there's a transmission on the encrypted talkgroup).

Mine isn't ADP, it's AES-256...but both AES-256 and ADP mute on FDMA on the x36-series radios.

 

[AZScanner]

Sounds like the scanner is missing the data in the call grant that tells it that this is an encrypted channel. I don't have a Phase II system up here I can play with (yet) to confirm this, but I ran into a similar problem with SDR# ad Unitrunker a while back. Unitrunker kept trying to tune talkgroups I knew were encrypted because it missed the call grant data telling it that the talkgroup was encrypted. I'm not familiar enough with the Phase II protocol yet to answer for certain, but it sounds like unless you catch the transmission from the moment it was originated, the scanner won't know it's listening to encryption. If that's the case, I'm not sure what if anything Uniden will be able to do about it.

As for the posts up above about how "scrambling" works on P25, I've never before in my life heard such nonsense. It works nothing like that - we have hundreds of encrypted talkgroups on the systems I monitor, and none of them sound or work as the poster described.

-AZ

 

[KevinC]

Sounds like the scanner is missing the data in the call grant that tells it that this is an encrypted channel. I don't have a Phase II system up here I can play with (yet) to confirm this, but I ran into a similar problem with SDR# ad Unitrunker a while back. Unitrunker kept trying to tune talkgroups I knew were encrypted because it missed the call grant data telling it that the talkgroup was encrypted. I'm not familiar enough with the Phase II protocol yet to answer for certain, but it sounds like unless you catch the transmission from the moment it was originated, the scanner won't know it's listening to encryption. If that's the case, I'm not sure what if anything Uniden will be able to do about it.

As for the posts up above about how "scrambling" works on P25, I've never before in my life heard such nonsense. It works nothing like that - we have hundreds of encrypted talkgroups on the systems I monitor, and none of them sound or work as the poster described.

-AZ

I don't think it's missing it in the call grant as it works fine on FDMA (the difference in FDMA and TDMA call grant isn't different enough).

When the PSR-800 first came out their version of "mute" didn't work on P2 either, but I worked with them and they got it going.

 

[AZScanner]

I don't think it's missing it in the call grant as it works fine on FDMA (the difference in FDMA and TDMA call grant isn't different enough).

When the PSR-800 first came out their version of "mute" didn't work on P2 either, but I worked with them and they got it going.

Cool, sounds like it's doable then, so this issue is but a firmware fix away.

-AZ

 

[KevinC]

..so this issue is but a firmware fix away.

-AZ

In theory...

 

[AZScanner]

In theory...

Well, to be fair, I didn't say which firmware update it would be... or when. :lol:

-AZ

 

[ecarvalho]

PT0 PT1 transmissions

I searched for PT0 and found this thread.
My 536 is picking up PT0 and PT1 this morning from the Virginia Loudoun County Dulles Dispatch (TGID 2805) frequency - which wasn't happening until about 8:00 am. Audio is clear and I even turned on my old GRE PSR-800 and noticed the same except the GRE either didn't show anything or showed D2 where usually, on P25 it shows "DG".
Both scanners received these PT0 and PT1 transmissions clearly.

 

[darunimal]

Phase I and Phase II transmissions