This could be of some additional guidance. . .
If you'll look under the Tag column in the database associated with post #3 above, it may help clue you in as to how the channel is used.
Things with "Dispatch" are the primary channels - essentially where the dispatcher tells the responders to go along with the nature of the call. You'll also hear things like units calling in and out of service, status reports, traffic stops, etc.
There's a blurry line on "Talk" and "Tac" channels. Any communications relating to an event, call for service, detail, etc., that may be lengthy or otherwise tie up the dispatch channel will most likely be conducted on either a "Talk" or "Tac" channel.
This is by no means a hard and fast rule, rather some general idea of how channels are used.