Since fire uses fire ground channels, can the 800mhz simplex channels not be analogue that would link back into a p25 trunk?
That is similar to what is being done today with the TPS system:
FGround =>Vehicle Repeater=>Trunking TG
The problem is with the codec that is used to digitize the voice audio. Apparently, the audio quality when made digital is very bad. Dangerously so according to the IAFF.
Having said that, if the fire ground operations are all being done using the analogue vehicle repeater that may not necessarily be as big of an issue. Those monitoring the FG operations on the digital (P25) system may not be able to understand the firefighter, but those on the scene may. However, I'm not sure if that is adequate.
They may require that Toronto Fire dispatch and responding vehicles need to understand what is going on on the scene. That would make sence, since they usually patch the FG to a tactical channel so that it goes out over the Talk Group to other vehicles and TF dispatch.
Victor