If I understand correctly about what you are asking about, you are wondering about the tones that alert what rig is being dispatched correct?
If this is what you are asking, Aurora fire has these tones 24/7 that go off in the station when that station is being dispatched for a call. During the night (after 5pm I believe), the main dispatch goes silent in the station for some peace and quiet, however when the alert is send to that station, the dispatch becomes verbal again. It is NOT set up to where the bay doors open, or the lights come on or anything, its just the tone that goes through all of the speakers in the station. Also, if you program the TG for Station Alert #2 on the RR frequency database, you will hear a "telephone" type squak, which means that an alert is being sent to any one of the 15 Aurora Stations.
The Alert Tones go as followed:
Engine Company: Low-High
Truck Company: High-Low
Battalion Chief: High-Higher (beeping)
Heavy Rescue or HazMat: High-Low (same as the truck because the truck companies out of station 2 and station 8 are trained on those specialty rigs and that truck company goes out of service when a special response is needed)
Hope this helps...