Motorola Select-5 decoding. Help required

[Frasso]

Hi!
I'm trying to decode these selective calls.
I know they come from a radio system that uses motorola gm series.
From my research I think it's Select-5

I'm using Sorcerer to test decoding, but I don't know the standard used.

I provide an audio sample of one of the recordings that I tried to decode

https://drive.google.com/file/d/11tRj4Xb8Phj7R-fjXIaNgpugkoz9AzP3/view?usp=drive_link

 

[mikegilbert]

Unfortunately your link requires access to listen.

You should be able to attach the file directly in the forum.

 

[Frasso]

Unfortunately your link requires access to listen.

You should be able to attach the file directly in the forum.

I Have added another sample

 

[Ubbe]

It sounds like EEA that uses 40ms tone lengths and it's more than 5 tones, so probably adds it's own ID at the end.

/Ubbe

 

[Frasso]

It sounds like EEA that uses 40ms tone lengths and it's more than 5 tones, so probably adds it's own ID at the end.

/Ubbe

I have tried all available standards, including EEA without success.

Maybe some settings on sorcerer are wrong or the signal is not strong enough

I know that is an ambulance dispatch (here in italy) and I know that those are the status the ambulances send.
I'm expecting to see some text like "N. of ambulance on scene/back to base"

 

[Ubbe]

Look in its FFT spectrum display if you see the signal there. I downloaded the program and only see my own windows sounds appearing but not when playing from a file. It seems to only decode live audio. Maybe there's a way to redirect the audio from the file in some way but I have so far no success with that.

/Ubbe

 

[Frasso]

Look in its FFT spectrum display if you see the signal there. I downloaded the program and only see my own windows sounds appearing but not when playing from a file. It seems to only decode live audio. Maybe there's a way to redirect the audio from the file in some way but I have so far no success with that.

/Ubbe

For redirect the audo from the file I used VB cable.
On Sorcerer go on File > options > sound card optitions.

 

[ff026]

Sounds like MODAT.

 

[Frasso]

Sounds like MODAT.

I think that it's zvei or ccir

 

[ff026]

I think that it's zvei or ccir

Take a listen.

MODAT - Signal Identification Wiki

MODAT is a 7-tone Automatic Number Identification (ANI) status system used by handheld radios. It provides unit ID and emergency statuses to receiving radio sets when transmitted.

www.sigidwiki.com

 

[Frasso]

Take a listen.

MODAT - Signal Identification Wiki

MODAT is a 7-tone Automatic Number Identification (ANI) status system used by handheld radios. It provides unit ID and emergency statuses to receiving radio sets when transmitted.

www.sigidwiki.com

Yeah...it could be.
They sound a little all the same to be honest😂

 

[Frasso]

This is what I see on the waterfall

 

[kf8yk]

I think this is Hexadecimal Sequential Code (HSC) format.

HSC uses tone frequencies & timing similar to EEA/CCIR 5 tone but allows sequences much longer than the common 5/6 tone format.

Here's an application note with the details: HSC Signaling

This format has been around a while but was not a popular option in North America. The old ACC RC-850 repeater controller even supported it: RC-850 HSC

Using the HSC format on your first audio file both tone bursts decode as: 0295111901, all tones were EEA format & 40 ms timing.

 

[Frasso]

I think this is Hexadecimal Sequential Code (HSC) format.

HSC uses tone frequencies & timing similar to EEA/CCIR 5 tone but allows sequences much longer than the common 5/6 tone format.

Here's an application note with the details: HSC Signaling

This format has been around a while but was not a popular option in North America. The old ACC RC-850 repeater controller even supported it: RC-850 HSC

Using the HSC format on your first audio file both tone bursts decode as: 0295111901, all tones were EEA format & 40 ms timing.

That's interesting...

Is it possible that what you have decoded "0295111901" on the radio (a motorola gm family) is shown as text?

The first brust should be from the ambulance the second from the dispatch

Like "back to base" "copy"

 

[kf8yk]

Is it possible that what you have decoded "0295111901" on the radio (a motorola gm family) is shown as text?

Unlikely it's text, in the HSC format a 'B' tone would precede a block of text & there's no B tones (930 Hz) in your recordings.

Usually status messages are not meant to be plain text readable, typically one or more of the digits encodes the status (1=enroute, 2=on scene, etc.) and the remainder are the unit ID. Log all the messages & look for a pattern.

If you look at the Euro GM300 sales guide on page 45 it shows how this radio can be programmed use 1 to 8 digits for unit ID and 1 to 3 digits for status codes.

 

[mikegilbert]

Seems like they're using the 5-tone as status messages.

 

[Frasso]

Seems like they're using the 5-tone as status messages.

Yes it should be like that.
I tried deciphering the numbers that way.
I found a document where these states are specified. However, it only indicates 2 buttons for a total of 4 sendable states...

It's unfortunate that the content is only numeric, it doesn't make identifying the radio system any easier