There is alot of concern that it is against NFPA standard to use a trunked system on fireground operation
QUITE TRUE! This is a huge problem, as often portables on trunked systems have difficulties within buildings etc. Some agencies have taken to using the ITAC channels in simplex mode (not real proper use of these...) for fireground use, others have made other arrangements with 800 MHz. freqs or carry sepearate radios.
At a recent communications conference several of us cornered some manufacturers reps from Motorola, Ma-Com/Tyco/Ericsson?GE (or whatever they are called this week...) Vertex/Standard and Kenwood and asked/begged/pleaded for dual or multi-band public safety portable radios. We explained that simplex is required by communications guidelines for fireground operations, and use of the TRS is a waste of resources. The multi-band radios were requested to allow VHF users (which include most FD's around here) to communicate with UHF users (most PD's around here) as well as the 800 MHz. users (more and more agencies all the time).
Interoperability is defined differently by different people, we defined it as being able to talk to thier radio with ours with no additional equipment. Venders want to sell you whiz-bang technology that costs big bucks and needs an engineer to operate. I guess multi-band radios are too simple. Hams have been doing it for decades...