This is what they call “two-tone” paging. Each pair of tones will wake up a voice pager. They woke up every firefighter’s pager, then a single voice message came on. Some of the fancier voice pagers recorded this audio. The audio is FM with 5 khz of deviation.
Custer county Nebraska my dad was a firefighter in the 2000s and when he still hear these tones after leaving the fire and rescue he gets so mad for me listening to the scanner when it goes off
I saw a couple of firefighters that may carry a walker talkie radio and they had fire pagers that you can also listen to police calls on them like a scanner.