ASTRO 7.x Site Alias'?

[trumpetman]

Do true P25 systems have the ability to put out an alias like SmartZone systems do? The VIPER system in NC puts out a 6 character alias for each site that can be displayed on some scanners and radios.

I've never noticed anything on the sites I've monitored in NC & SC, and I don't see any listed for statewide systems in Colorado, Virginia, etc.

Does anyone know if these sites provide a means of identifying themselves on radios, and if so, how is that data transferred.

[Unitrunker]

Motorola P25 systems will do this. The text can be up to eight characters long. It is usually set to the FCC callsign but the administrator could set this to anything. I don't know if this text appears on the radio.

[MattSR]

Hi Rick,

Is this a site ID or System ID? Where abouts in the P25 data stream does this info get conveyed across?

Matt

[Unitrunker]

It seems to be unique per site. It has a Motorola MfgId of 0x90. Run Unitrunker with decode logging to see all the details.

[MattSR]

I'm using wireshark with OP25 to look at the raw frames - I'll load up Unitrunker and Pro96com to have a look, but would you happen to know the TSBK opcodes for the command?

[mikey60]

I've seen a string on an CWID grant (Motorola specific), but I've never seen one anywhere else. Some scanner listeners have confirmed that the information being sent on the control channel in this grant is the same characters being transmitted in CW on that frequency.

Mike

[Unitrunker]

Its been a while but six or so years ago I was looking at a Motorola P25 system console. It was Windows 2000 I think (or maybe Windows Server 2003). The Motorola Zone Configuration manager screen provides a list of channels. Next to each channel was a check box for "BSI" and a place to enter a short text string. BSI is base station identification. It's the Morse code identifier Mikey describes.

In the US, system administrators typically check BSI on the channel with the lowest frequency. BSI channels are also usually held in reserve as are alternate control channels. These channels are only used for voice when all other voice channels are busy.

BTW, Matt - nice video presentation last month!

[MattSR]

Thanks Rick - t was kinda thrown together at the last minute but I never thought I could talk about the "known plaintext attack" for that long!