Batboard

Ok, like many people (I am sure) I am well versed in the Astro 25 CPS in the common areas. General Conventional programming and Trunked programming.

However, one part (I am ashamed to say) I have never ventured into (due to no one needing it) was the "ASTRO System" in conventional mode.

I am sure its simple to use.

But

1) What is its purpose? Why would you need to use an astro system in conventional mode? Why not just program the trunked system in? (Unless it was a conventional only radio)

2) Is there any special way to program it? Do you need system keys?

Astro is not just for trunking. There are many astro conventional systems out there. You do not need a system key for conventional astro or analog. You would need tx and rx freq's and Nac code to start.

You are right, there are that.

I apologize, as my post was not clear enough.

I definitely realize there are ASTRO conventional systems.

What I am referring to, however, is the portion where you can apply talkgroups in a conventional mode.

Not "Astro Conventional", but rather Astro Trunking in a conventional mode?

Okay, I gotcha. I'm not sure what exactly they are for, but it's not trunking. I think it just allows more than 1 group of users to share a conventional channel or repeater without hearing each other.

Last poster is exactly correct, this allows multiple groups of users to share the channel without hearing each other provided that all of the radios are set for selective squelch (only unsquelch on address match) rather than digital squelch (unsquelch on correct network access code).
It isn't a good idea. Although it seems like and equivalent of multiple CTCSS/DCS codes on an FM conventional channel, Astro is much more sensitive to doubling (transmission is likely to be lost completely rather than creating a squawk which prompts the intended receivers to ask for a repeat).
The standards allow it but it isn't sensible to use it.