You can use any of the modules that plug into the Selectone units in the Aux port on the EOWS controller board. You probably could also use the tone 33 UTM module, the "Selectone custom tone module" to have FS record a custom WAV file and play it via the EOWS as well. For instance, if you wanted to record a Navy H8 Klaxon and play it through the EOWS you could do so, the module has a 16-second loop.
So, right off the bat you have at least 33 possible tones plus what's hard-coded on the motherboard. I have the slow whoop from a Selectone in my EOWS garage unit currently, it's tone TM9 on the Federal tone index. I've got like 5 other tone modules on the shelf for it.
http://www.federalsignal-indust.com/def ... 7&lookup=5
I would think one limiting factor would be the low frequency cutoff of the tone depending what was recorded on the custom module. Too low a frequency and you blow your speaker drivers....
Take care
Eric