What is SMR?

[thess416]

I'm sorry if this has been asked before... but what exactly is "SMR"? I'm in central North Carolina and several counties have "Fayetteville SMR" as an operating TRS. The system list several sites but has a relatively low number of talk groups, furthermore... many of the TGID's are duplicated on another system. So I'm wondering if there is something I'm missing.

Also I'm wondering about P25. The main TRS's I listen to are Motorola type II, when someone talks my scanner flashed "LNK P25" Does this mean it's a P25 system or P25 compliant or what? I've noticed other systems are labeled P25. So whats the difference?

If anyone is wondering I'm using a BCD396T

[DaveNF2G]

SMR = Specialized Mobile Radio

This was the FCC's designation for land mobile trunking when these systems first became available.

[immelmen]

do a google search for "APCO-25" and you will find all kinds of info. Moto type II TRS are not true P25 compliant TRS as they still use proprietary 3600 baud CC. APCO Project 25 TRS use 9600 baud control channels.

However, moto type II systems (esp. smartzone) do often use CAI (common air interface) for digital voice transmissions, which is the APCO name for IMBE (improved multi band excitation). IMBE is the P25 standard for digital voice.

Fayetteville looks like type 2 smartnet- (there is no digital p25 voice, analog only). Looks like the nearest digital voice to you would be the smartzone system at brag. or the VIPER system. additionally, there are no pure P25 compliant 9600 TRS in your county, according to the database.

that is a VERY basic quick and dirty to help point you in the right direction for some research.

[DaveNF2G]

SMR has little to do with P25, except that the Project 25 standard is a new way to build public safety "SMR" systems.

[thess416]

Thank you all so much for the info. The VIPER System is the system I was referring to when I was talking about my scanner flashing the "LNK P25". The county next to mine is EDACS Pro Voice, and a few counties over has just created a new P25 system... but I have no info on the talk groups yet. So basically the VIPER system is not a true P25 system because because it used the proprietary 3600 baud control channels? So I assume that the TGID's using the CAI are P25 compliant, thus the P25 link on my scanner.

Thanks all for the information

[wayne_h]

Specialized Mobile Radio. It's what the FCC calls commercially run trunked systems in the 800 band that profit from their services.

Previous to Nextel these were prolific and great income generators.

http://en.wikipedia.org/wiki/Specialized_Mobile_Radio (Mostly correct but there's some interpretation there)

[immelmen]

Originally Posted by thess416

So basically the VIPER system is not a true P25 system because because it used the proprietary 3600 baud control channels? So I assume that the TGID's using the CAI are P25 compliant, thus the P25 link on my scanner.

Correct, VIPER is not, as a TRS, P25 compliant. It just so happens the mode for voice transmissions used on the system, IMBE, is the Project-25 standard (CAI) for digital voice. The talkgroups using CAI are still not really P25 compliant however, because they still trunk with the older 3600 baud system.

[DaveNF2G]

Originally Posted by immelmen

The talkgroups using CAI are still not really P25 compliant however, because they still trunk with the older 3600 baud system.

Yes, they are compliant with the part of the P25 standard describing how digital audio is to be generated. The fact that a trunked system is not using a P25 standard 9600 bps control channel does not render the digital audio on that system noncompliant.

[immelmen]

Originally Posted by DaveNF2G

Yes, they are compliant with the part of the P25 standard describing how digital audio is to be generated. The fact that a trunked system is not using a P25 standard 9600 bps control channel does not render the digital audio on that system noncompliant.

correct, I didn't think I suggested otherwise. As I stated that IMBE audio, no matter the system, was the P25 standard, (ie. compliant). My understanding of the question (thess416 correct me if I am wrong) was that it asked, black or white, if the Talkgroup was P25 compliant. No talkgroup on a 3600 system is P25 compliant even if the voice mode is.

thess416, I am not familiar with that scanner, but I would guess the P25 message on the screen is because it is receiving P25 standard voice on that (Motorola)talkgroup. Possibly someone else using this scanner could confirm.

[thess416]

immelmen, Yes... you were correct. I assumed that the specific talkgroup was P25 compliant because of how it was digitally generated. On the VIPER system, there are a mix of analog and digital.

The system here is kind of new and I still have a lot to learn, but it was my impression that part of the appeal of the system was the P25 standard.

Thank you all for the information

[Cowthief]

Hello.

Correct, P25, but not quite.
However, if you take a Motorola Astro Sabre talkie that is set up for 400 MHz trunking and configure it for conventional, it will work just fine as a P25 compliant radio.
Remember that the government models may come in some wild splits, so be careful what you buy.
But, depending on what you buy, you may be able to get a non-trunking fully P25 compliant talkie for cheap.
And, yes, NextHell has pretty much ended the smaller radio shop, that and the cellular carriers.
But, not only can you monitor this, for the correct user, this type of radio can be just what you are looking for.

[DickH]

[QUOTE=thess416;849242... but what exactly is "SMR"? [/QUOTE]

SMR is RMS backwards (Root Means Squared).

[stlouisx50]

Can you listen to SMR on a scanner? All I hear is what sounds like fast blips then nothing, then fast blips then nothing...

[wayne_h]

SMR is more how a service is used and is not specific to a technology. More or less it's a for-profit trunked system operating on 800 or 900.

[stlouisx50]

How does one listen to it via scanner?