There use to be a program on android and iPhone in the play store called radio Id, which would decode mdc, quick call 2, dtmf, ge star and single tone. While it was a few dollars it was worth it.
Just throwing that out there. The creator I believe is a member on radio reference but I forget his name.
You may want to check it out.
It has helped me in some instances including work related in reading mdc ids, or testing a tone out on qc2 over pulling everything out the pelican case.
In any sense with a scanner you can see the mdc ids or ge star if used.
It pulls the audio from air from scanner then decodes.
I should add while it was a few bucks, it beat the free pc decoder types and never was wrong.
The few dollars goes to the creator.
If you are a member of a vfd contact your chief, radio admin, or s.o. and they should be able to give the decode tones.
If they use encode alarm on a tower ie siren then they may be hesitant. But it is moot since Joe public can decode the 2 tones for encode and decode for the tower siren box.