I'd say probably not. In my department every firefighter gets a 4 digit number the moment they join. You don't get a radio until you've proven some level of dedication to the chief's satisfaction. That usually includes making duty nights, trainings and meetings regularly for at least your first three months.
We always use our unit number on the radio but it's also used in reports and a lot of times just in discussion around the firehouse. When it's casual we tend to call everyone by name but if it's FD business we sometimes use unit numbers.
no. thats just a number to use if you have a radio with you. say you are on an interior team, and you take a radio with you. you can use that number as your identifier so that IC knows who they are talking too.
Also, like eric said, a lot of depts give a four digit number, usually a 2 digit dept number and a 2 didgit personnel number. this is for accountability purposes.
In some depts only officers are issued radios, with additional radios carried on the apparatus for use at a scene. officers normally have a radio number that is different than their accountability number
There is a simple way to ID the radios - simply have them broadcast the apparatus riding position instead of a specific firefighter's identifier when radios are shared across shifts or by volunteers.
My department uses a riding assignment system similar to FDNY's...
The only small issue we had is that due to the Motorola screen abbreviations initially "E1-0" for "Engine 1 Officer" was answered as "Engine 10" by the dispatchers.
We fixed that one with about 30 seconds of additional training.
You can also use "Team" labels for the narrowbanded radios "Team 1", "Team 2", etc.
If two team members have radios, you can ID them as "Team 1-Alpha" and "Team 1 Bravo".
If you use complicated numbers to identify individuals, it will cause problems when you run mutual aid, have a MAYDAY, etc.
One other thing - our chief officers are issued individual radios. My identifier (radio and Passport Accountability ID) is always "Car 20" and my mobile and handheld radios transmit that ID every time I key up.
Follow the KISS principle - Don't make it more complicated than necessary.