There is another run "criteria" in which they use "FG 6" (digital) and, on rare occasions (depending on what kind of run it is, and how busy they are) "FG 7" (digital). In theory (and in practice) you could have five different types of runs (building fire, gas leak, car fire, EMS run, automatic alarm, etc) and have companies operation on five different frequencies, a SERIOUS and DANGEROUS practice.
They also have used "FG 12" for drills.
One night, after a day-time drill, they had a fire, and one fireman was giving a report on "deteriorating conditions" inside the firebuilding...on "FG 12." Of course, no one at the scene heard him and, at some point, the dispatcher acknowledged him, but just told him to switch to another channel, and did not immediately relay his message to the IC (I would hope the dispatchers do better when the next message off-channel is a Mayday).
The other problem is: do they have the Dispatch manpower to cover all those channels at the same time?
For some reason, people fail to remember that, during the rip-roaring 1970s, departments like JC, as well as the FDNY, operated on ONE borough frequency for each borough regardless of how many fires were going on at the same time. On top of that, there was only ONE fireground (handie-talkie) frequency citywide (153.83).
Remarkably, all the fires were put out.