Astro 25 trunking on Astro Saber

Logitec · Post by **Logitec** » Thu Apr 04, 2002 10:24 am

I know that Astro 25 trunking (9600 baud)is an option for the Astro Sabers. I also know that it has to be a 1 meg radio. Does anyone know what other requirements there are for the radio to work on Astro 25 (host, DSP version, ??)? Thanks in advance.

Elroy Jetson · Post by **Elroy Jetson** » Thu Apr 04, 2002 7:27 pm

As a matter of fact....the CURRENT (latest) firmware for 1 meg Astro portables is as follows:

Host 7.07.00
DSP 7.03.20

That should be the latest and greatest. This is a confirmed matched pair of revisions. If you see one in a radio, you should see the other as well.

Beyond that, you of course need to have the right options in the radio. Astro 25 trunking is an OPTION, as you know, and it has to be flashed in.

To be exact, the 11th digit in the flashcode needs to have a value of 8 or more. Like this:

Flashcode 000000-000080-0 (other codes removed for simplicity's sake)

The 8 indicates Q361/G361 Digital APCO-25 IMBE Trunking (9.6KB control channel data)

This number can be higher, but it MUST be at least 8 or you do NOT have Astro 25 digital trunking capacity.

A word of caution: Every Astro 25 digital trunking system I've ever heard of was a full-blown SmartZone system as well. Special techniques will be required to monitor it safely, the best of which is the 'hidden channels in each zone' trick.

Monitoring such a system can be done safely, but it does have its hazards if you don't know the tricks that keep the radio from transmitting under any circumstances.

If you don't know what the hidden channels in each zone trick is, let me know, and I'll post it for you...but you may be able to find it around here somewhere. I've posted it a few times recently.

Elroy

Logitec · Post by **Logitec** » Thu Apr 04, 2002 9:29 pm

Thanks for the replies. That's great information. Elroy, I am familiar with the hidden channels trick. One thing I would like to clarify; I was thinking that if you had the Q361 option, you would not have (or need) the H38 option. I thought the Astro 25 trunking systems had similar features to Smartzone, but were not technically Smartzone systems. But it sounds like you are saying that you would need both features in the radio. Is this right? Thanks again.

CHEFA2001 · Post by **CHEFA2001** » Thu Apr 04, 2002 9:35 pm

Elroy, Are you sure about the required flashcode for this, as my radio has following flashcode and currently monitors such a system:
591008-4f1e00-9.

Please let me know your thoughts

Elroy Jetson · Post by **Elroy Jetson** » Fri Apr 05, 2002 1:52 pm

Load up your RSS, load your radio's file, go to the main menu, and hit this key sequence:

f4-f4-f3-f9-f2

You should now be at Astro 25 trunking system options.

If you didn't get to that screen, you don't have Astro Project 25 trunking in your radio.

Also refer to page 378 in your RSS manual, version K.

Astro 25 trunking is NOT the same as CAI trunking.

Astro 25 trunking uses a 9600 baud control channels and the system is purely digital. It has NO analog talkgroup capability. An Astro Saber or XTS3000 or 3500 with this option enabled is also INCAPABLE of CAI digital trunking due to space constraints in the firmware.

CAI digital trunking uses the same 3600 baud control channel as conventional trunking, with analog or digital groups being available on a mixed basis.

Astro 25 is NOT CAI. Different animals.

Elroy

Post by **wavetar** » Fri Apr 05, 2002 4:49 pm

IMBE (Improved Multi-Band Excitation) is the process used to covert analog to digital internally in the radio. Do not confuse it with what goes on outside of the radio, as far as 3600kbs vs. 9600kbs systems. It is used in both CAI & Astro-25 radios, no differences.

Todd

Elroy Jetson · Post by **Elroy Jetson** » Fri Apr 05, 2002 8:33 pm

No.

Yes.

Astro 25 uses a variant of the IMBE codec, as I understand it, but it is not fully IMBE compatible due to the fact that it's a pure 9600 baud based system and it doesn't intercommunicate with 3600 baud systems.

To the very best of my knowledge, no Astro product that has up to 1 meg of flash memory can have Astro 25 and CAI in the same radio at the same time. However, the XTS5000, being an 8 meg radio, should have the theoretical capability to support both formats in the same radio.

Astro 25 trunking IS an APCO approved format. But only Motorola has a fully compliant offering available on the market.

The confusing part is, APCO compliance applies to more than one format.

CAI is an APCO compliant format, applying to the use of the IMBE algorithm and specific signalling and control formatting. CAI trunking is hybrid, because the trunking format itself is pure Motorola Smarnet/Smartzone, etc. but the voices are carried in a CAI compliant form. A CONVENTIONAL CAI compliant radio can monitor the TRUNKED digital voice traffic in such a system, because the digital voice traffic is fully CAI compliant.

Astro/Apco Project 25 compliant digital trunking is the "deluxe" digital format that is the desired migration path for those who believe in a digital future, even though digital has its problems that need to be ironed out.

True APCO Project 25 pure digital trunking should not be referred to as Astro trunking, because that's not the 'correct' term for it.
Motorola sold proprietary trunking systems that weren't fully APCO compliant, and they were and are called Astro systems. The upgraded ones are properly called APCO Project 25 systems.

Yes, it's confusing. Tell me something I don't know.

Elroy

JohnG · Post by **JohnG** » Fri Apr 05, 2002 10:46 pm

9600 bps ASTRO 25 trunked radios do offer "limited 3600" operation in analog/IMBE digital mode. Last I checked, "Limited 3600" basically only gives you talkgroup dispatch operation.

Transcrypt/EFJ also offers a 9600 APCO trunked mobile and portable product. They recently issued a press release when they successfully demonstrated this for Phoneix/Mesa.

John

Post by **wavetar** » Sat Apr 06, 2002 4:11 am

My understanding is the IMBE codec is the same, regardless of whether or not the radio is "Astro" trunking or "APCO-25" trunking. Take one of each & program a conventional digital channel into them. They will talk to one another, so the codec itself is the same. The workings of the different systems is a whole separate story.

Todd

Twisted_Pear · Post by **Twisted_Pear** » Sun Apr 07, 2002 1:18 am

Re: 3600/CAI

I believe when the CAI is used it sends the information in the background data stream while on the voice channel. With APCO-25 trunking, the CAI isn't needed as the information is transferred normally via control channel communication, etc.