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DMR/NXDN and TONING

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milf

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#1
Not sure if this has been asked before: On DMR systems whether conventional, or Con + or CAP +: If an Fire or EMS agency uses toning, does it function like it does on analog? Sam for NXDN both NexEDGE and iDAS...

Now, with scanners that can do FTO, how would one set up to log the tones on DMR or NXDN systems? Same as for analog on conventional (And can this be done on an P25 conventional?

What about when the tones are sent over an Con + or Cap + TRS? Or NexEDGE or iDAS TRS?
 
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#2
Not sure if this has been asked before: On DMR systems whether conventional, or Con + or CAP +: If an Fire or EMS agency uses toning, does it function like it does on analog? Sam for NXDN both NexEDGE and iDAS...



Now, with scanners that can do FTO, how would one set up to log the tones on DMR or NXDN systems? Same as for analog on conventional (And can this be done on an P25 conventional?



What about when the tones are sent over an Con + or Cap + TRS? Or NexEDGE or iDAS TRS?


AFAIK 2 tone only has recently been supported by P25, except the tones are not run through the vocoder. The vocoder recognizes the tones but does not digitize the actual tone.

Also AFAIK 2 tone, or any analogue signalling protocol, will not work properly over DMR(any type) or NXDN(conventional or trunked).


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milf

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#3
Strange as IU Health LifeLine tones multiple times daily on a Con + TRS. Both for alerting for pager and radio testing, and to tone Helo and Ground units for call outs. And its not being multicast from analog, as they are not dropping the tones over the VHF analog local. So not sure how exactly that works. So currently there is no way to log tones on these systems? Oh well.
 
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#4
Tones can work on any digital system, as long as the vocoder doesn't change the audio frequency of the tones.

The only challenge is getting the audio from the system radio to whatever is decoding the tones.
 

jasday

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#6
I'm not sure how it works with DMR, but the way that our agency used the two tones was just for audio only. We are on a P25 system. The radio console would send out a digital page to "alert" the portable and station radios. The radios would receive the digital call alert opening speakers and turning on lights, the audible two tones would play and then information would be voiced. Since those are digital formats (correct me if I'm wrong, I don't know very much about those system types) i would assume it's the same and the consoles are sending a digital page and the two tones are audio only.

For a while, we were getting some interference at one of our stations and had to go to using analog two tones for stations and portables.

We are now using a automated dispatch system through US Digital Designs and everything is carried over IP
 

milf

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#7
Sounds like something to ask the DSD+ folks. Surely that's the kind of functionality that belongs in a system analysis tool.
I was hoping for the easy way.. Thru my BCD436HP,.... aBut yeah DSD+ or TTD would probably end up being the current only way... Here is to wishing that maybe Uniden has plans for the SDS100 in a FW update maybe once it hits and is really getting truly field tested? Or when the Whistler TRX-100/200 get here?
 

milf

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#9
Cool, buy me one and I will figure out how in heck to pull the data off so it can be logged in the wiki etc.... Did not know the Unication did DMR or NXDN. :) Analog, yah, P25, yah...
 
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#10
It's done by Meridian FD on our ComSouth Con+ system, I'll have to look further into if it activates anything. From my experience there is not even a way to set it up over connect+ with the way the radios are programmed from an option board.
 
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#11
P25 uses IMBE or AMBE; P25 TDMA, NXDN, and DMR use AMBE+2; and Yaesu Fusion, D-Star and OpenSky is AMBE. These codecs are designed and optimized, taking advantage of the complexity and constant changes, for the human voice for compression efficiency. That said they perform very badly for steady sounds. Also these schemes can be designed to deliberately block steady or nearly steady sounds such as a siren permitting only the voice to pass. Using tones on these systems is a bad idea and systems like P25 supports a variety of apps; text messages, fire & EMS alerting and automation, SCADA, location services, and geofencing (every dispatched to an incident is automatically switched to the proper channel). It does make a sloppy mess with patches from analog, tones and stuff like Fleetsync get garbled.
 
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#13
Cool, buy me one and I will figure out how in heck to pull the data off so it can be logged in the wiki etc.... Did not know the Unication did DMR or NXDN. :) Analog, yah, P25, yah...
The Unication pagers does not handle DMR or NXDN as far as I know. They sort of do two tone alerting on P25 if you know the tones information ahead of time. I haven't really seen too much feedback on that feature. I don't think that they can be used to log tones since they are not designed to discover new information.
 

Ubbe

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#15
Tones can work on any digital system, as long as the vocoder doesn't change the audio frequency of the tones.
The problem is that all digital radiosystems uses vocoders that doesn't transport all the bits lossless over the radiowaves. They always use compressing techniques that they remove bits and the decoder then tries to guess what has been removed and add bits. The result is a highly distorded tone. And many systems also have filter algoritms that try to cancel any constant audiosignals like background noise and tones which makes it impossible to transfer a clean tone over any digital vocoder system used in radiosystems.

/Ubbe
 
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#16
The problem is that all digital radiosystems uses vocoders that doesn't transport all the bits lossless over the radiowaves. They always use compressing techniques that they remove bits and the decoder then tries to guess what has been removed and add bits. The result is a highly distorded tone.
Actually, that is not true, because a pure sine wave is the most compressible waveform. Mathematically, it requires the least information to describe, because it is a single frequency at a constant amplitude, unlike human voice, which is a complex mix of constantly fluctuating frequencies with constantly varying amplitudes. Lossy compression algorithms are designed to mathematically simplify the complex mix of frequencies and amplitudes in a waveform, so that fewer bits can be used to encode the waveform. A pure sine wave at a constant amplitude already requires the least number of bits to encode, so it will pass through compression with the less total harmonic distortion than speech.
 
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#17
Motorola began offering two-tone over P25 not too long ago. I've never had the opportunity to play with it though as most of the departments I deal with on a regular basis either use Astro 25 subscribers (it's only featured on the APX line) still or just have a multi-select which pushes it out to an analog two-tone consolette as well. For the latter, the tones still go out (toning is controlled by the console) OTA on the digital group of interest but it still comes out highly distorted (example, 1000 Hz audio and a 1011 pattern sound completely different).

The problem about using a page/call-alert function is it is typically only a single ID page so it may not always be effective to page a large group at once. The only way to page a group is to key-up the entire talk group of interest. I've seen some setups for station alerting where a two-tone page is decoded by a dedicated receiver and closes a relay, triggering lights and strobes as well as closing an additional relay with the audio of a digital radio to the PA system allowing audio over the digital side to be put across the station. Also as stated, many station are moving to US Digital and other IP based solutions for station alerting and keeping the old paging method strictly for backup.
 
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#18
Motorola began offering two-tone over P25 not too long ago. I've never had the opportunity to play with it though as most of the departments I deal with on a regular basis either use Astro 25 subscribers (it's only featured on the APX line) still or just have a multi-select which pushes it out to an analog two-tone consolette as well. For the latter, the tones still go out (toning is controlled by the console) OTA on the digital group of interest but it still comes out highly distorted (example, 1000 Hz audio and a 1011 pattern sound completely different).
The local P25 systems I monitor broadcast tones for every dispatch call without significant distortion, so if tones over P25 are getting distorted, it's due to incorrect gain staging or some other connection problem between the analog tone console and the P25 transmitter, not the P25 vocoder itself.
 
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#20
https://1drv.ms/u/s!ApJIS-l4xqPtgvNwuMfsmbu0-UYTiA
A tone dispatch recorded off a P25 system with my 536. The tones are not "highly distorted".
That's using tone patterns (similar to the 1011 pattern) and not actual analog injection through the vocoder.

Take something like an Aeroflex or Freedom analyzer and inject a 1000 Hz (or even two-tone if you have that ability) onto a monitored channel with a SU. You'll hear something completely different.
 
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