Like I said the calls go to the stations over the internet not over the air so there are no station talk groups.
The calls are rebroadcasted over the air. And I agree, I liked the original Locution format.
That's actually what I thought too until I was in the router closet of our station trying to fix something a couple of months ago. There was a base station radio that was sitting on talkgroup "PA ##." It was sticking out like a sore thumb because in the dark closet, the green glow of the backlight was lighting up the back of the closet behind one of the cabinets. When I asked about this, I got a history lesson!
There are actually 5 ways that each station can be dispatched. When I first started, everything was still manually dispatched and the PA ## talkgroups is how each station was "hit" individually since you can't tone out on a trunked 800 system. When I first started, I still remember tones going out over the air, and that was because some of the township departments couldn't afford the tech upgrades to get the 800 paging system wired into their station so it was still going out over VHF for those stations. This is still used today when locution goes down and when they take it down for maintenance and we get dispatched by a human. In the old days, when EMS or fire alarms went out, each individual station was hit, but to speed up dispatching, between 0800 and 2000, if a report of a fire/working fire/multi-alarm fire went out, everyone's PA opened up. This was apparently to save time--the dispatcher could hit the button that said (for example) BN 1, and Station 1/9, Station 2/3, Station 8 and Station 25 (I think... I don't have the battalion/stations committed to memory) would all have their PA open up regardless of if any units would be assigned to that run. For larger incidents, such as Alert 2's or Jumpers, they actually had a button that could open up every station's PA. Obviously this is no longer needed in day-to-day ops since locution can accurately and quickly open up the PAs needed.
The second method is the IP method you are describing. Locution's data is actually stored on a box in the station (also in that closet!) that says.. "Locution" (surprise!) on it. When the data burst comes through, it picks the right audio files to play, and then plays it locally over the station PA. However, if the system downtown detects that the locution box in the station didn't properly trigger, it will grab the audio off of a box downtown, and play it over the PA ## talkgroup. This actually caused a problem at the beginning because sometimes locution would detect that the local box didn't trigger and send it over the PA so we'd have two messages going over the PA at the same time, but out of sync making the dispatch completely useless. They've now fixed this somehow (I'm assuming if the box is already going, then the radio can't also start using the PA?).
The third method is the radio TG "10 fire." Once again, the downtown locution box picks the audio clips, strings them together, and stacks them to be dispatched on 10 Fire. Obviously these have to go out sequentially.
For completeness, the fourth method is the MDT (which isn't up to NFPA standard I believe because it uses a verizon aircard) and the fifth method is the landline. The landline isn't actually a commercial phone line, but one that is hard wired to the FAO downtown.
So that was a really long way of saying that the station talkgroups actually still exist and serve as the backup for locution! You can actually find these TGs by using an open scanner and every once in a while you'll hear a locution dispatch on a TG that's not documented anywhere. If you keep track, I'm guessing someone with the time on their hands could figure out the DEC for each station TG in the city, but you'd have to have a lot of time on your hands! Locution has far fewer problems nowadays so the uses of the station TG's are few and far between. But with the ~50 stations that Columbus dispatches for, I can see why it might not be a high priority to find 4 free zones to stick the station PA talkgroups onto.