Harald is correct, there are generally no "alarm specific" fuses, they're all standard low-voltage stuff. Most are the glass tube with metal caps type like those on your PCB. The main electrical rating to look for is current, i.e., Amp rating. Any 1A fuse will work if you can make it fit into the circuit board's holder. As for voltage, I've seen lots of fuses in alarm control panels rated at 250V---that doesn't mean they operate at that voltage, it's just the maximum voltage at which they're supposed to be used. You can pretty much the ignore the voltage rating.
The replacement fuse obviously has to fit into the holder of the blown fuse, so obviously physical size is important. To be honest, I have so many spare fuses stockpiled that I haven't had to shop for a fuse for alarm control panels since back in the day you could just go to Radio Shack and root around in their bins, so unless you have an electronics store handy, I'd suggest measuring the length and diameter of your fuse, take a magnifying glass to look at all the specs engraved on the metal ends; and then go on eBay and search for "Glass 1A Fuses". You'll get about 2500 hits, some of which won't look like yours, or tell you the physical size; but if you search for it, you'll find some that does give you the specs to let you know it's the same as your fuse. You may be able to narrow down the Search with more specs from the fuse caps.
I'd buy more than one fuse, in case it blows again; and while you're at it, you might shop for replacement fuses for all three holders, to leave in, at, or near the PC3000 cabinet. I assume this is one of the array of 3 fuses on the top left of the PCB.
I don't necessary promote eBay to buy from ( I buy a lot there, but that's me), but their layout and abundant pix lets you look at a lot of choices without scrolling through so many pages.
BTW---How many peripherals do you have on your AUX output? You shouldn't be blowing a fuse there unless you managed to cross wires. I always recommend powering the panel down before connecting/disconnecting a peripheral device.