P25 trunking system keys

[MattSR]

Hi All,

Without anyone getting all high-and-mighty about illegally programming radios on trunking systems, can someone explain the differences in ASTRO25 trunking programming and system keys compared to the older 3600 baud "normal system key" method of programming.

Can proper P25 trunk systems (9600) be programmed without an ASK?

Cheers,
Matt

[Batwings21]

Can proper P25 trunk systems (9600) be programmed without an ASK?

So long as the radio has not been programmed with a ASK then yes.

[MattSR]

and the system key format is obviously different from the old 3600 ones?

[Batwings21]

Not sure, I would have to look into that. I only have legit keys, let me look at them and see what they look like.

[akardam]

Yes, you can use the legacy software system keys on Astro25 (9600) trunking systems... to a point. (Fair warning, most of this is from memory, and I haven't gone through the class yet, so some of the details may not be quite right...)

If you look at your CPS, you'll notice that under the Astro25 section of the Trunking System General tab, it referrs to the "Home System ID", as opposed to the Type II section, which referrs simply to a "System ID". The help file says in part "... three-digit ID of the in-the-field System ID on which this ASTRO 25 radio normally operates." (Empasis Mine). The reason for this is that P25 trunking systems are designed to be able to be networked together, and the overall network that any P25 trunking system belongs to is referred to by its Wide Area Controller Network (WACN) ID. If you read on in the help file, you'll see that the subscriber uses a combination of its ID, the Home System ID, and the Home WACN ID, as a unique identifier when registering with the network. Clear as mud so far?

Now, if you have a legacy system key file which matches the Home System ID of the P25 trunking system you wish to program, CPS will accept that (and it is the same format as Type II legacy software system keys, by the way). So, you'll be able to select the specific Home ID, and any WACN ID. Obviously, though, if you selected a WACN that didn't correspond with the one for your particular Home ID, the system would probably reject the radio's affiliation attempt. Motorola also says that a standard ASK matching the Home ID will behave the same way (any limitations on fields withstanding), although there's no evidence to date that they've issued any such Home ID based ASKs for P25 trunking systems.

However, that's only part of the story. If you look further you see there's a checkbox that allows you to enable Inter-WACN roaming. I'm a little foggy on this point but the way it was explained to me is that if this field is checked, and if you have more than one system (Home ID) within the WACN you select, this will enable the radio to roam to any Home ID within the WACN, even if it's not specifically programmed with the Home ID (and as long as it has the proper control channels programmed in).

Now, once you check this box, you have to have a special type of ASK called a WACN ASK, in order to select the appropriate WACN ID. Since legacy software system keys were never able to define a WACN, only a system ID, this means that in order to use this feature, you have to have your WACN ASK. Ask me (no pun intended) if I found this out the hard way...

So... long story short, if you're not using Inter-WACN roaming, theoretically you can use a legacy software system key. Whether you can get one legitimately or not is another question entirely...

[MattSR]

OK cool, that is interesting info and enough to have me keen to learn more.

Thanks for the info guys