sixwheeledbeast

It's probably not faulty. Photo of both ends probably best way to solve.

Tamper will cause the strobe to flash?

Loops in fixy band and pull everything through after seems easier? Use the coated band so you don't damage the outer.

I don't work on Galaxy much so can't remember if it's +ve or -ve up, either way worth checking and you shouldn't loose data. Maybe not from the manufacturer but had new cells come with thin transparent plastic warning stickers that you easily wouldn't notice and/or covered in bitter alice which can have high resistance spots if you don't clean the contact area. Worse thing about the bitter alice stuff is it can be an intermittent issue but tests fine with meter as the probes are sharp.

If the sensors are one way you can probably set it and walk round the house no problem, but you'll set it off if you walk past something on the way to the keypad in the morning. All down to how the system was designed. Is it a Powermaster or a Powermax?

Something under the coin cell? Check it's voltage. It shouldn't loose any programming, you should fix that.

So it's the phone browser then, be it missing plugins or not supported, would be expected. Try another browser on the phone on the chance it's only a iOS Safari thing?

Some port/service being blocked? Can you connect remotely on a non cellular connection to prove?

Dyn are a big company, I just don't think they take free accounts any more... if that's what your looking for. All are external in some way, think of DDNS as an "updating addressbook". You always ask the book with your password, it forwards you the new location. When I say own, I mean the router manufacturer may have settings to able one via them, a bit like DVR's have.

Where did I say compliant systems where inherently dangerous? Removing the need for user authorisation on alarms at the keypad would make the system no longer conform to EN50131.

Home visits? Your lucky if your allowed in the surgery at the moment...

If you could, it wouldn't conform with latest intruder regs any more. Maybe it has some BS or EN option for compatiblity? Connection to an intruder system I would see as an auxiliary, the fire "system" needs to work stand alone without this. If not you have a potential hazard waiting to happen when you need it most. In a domestic situation I'd be more interested in finding everyone than messing with a keypad.

Most routers have DDNS support. Some have there own service, or a limited selection of web ones. Better routers you can manually use pretty much any DDNS service. Most of the free web ones require you to manually login monthly.

have the router do it CGNAT is done by the provider to provide more connections on a single IP, most mobile data connections have CGNAT. For a wired connection it's unlikely

Assuming there is no CGNAT, yes Dynamic DNS will be fine. There is no IPv4 address space left so getting a v4 address is hard, especially for free.

Slightly related, the new Amendment 2 changes a number of things around cabling in escape routes. Only cables allowed are for use in that area, as short as practical. LSF, no PVC trunking (even with metal clips) due to smoke emitted. Anything low level, full mechanical protection so it can't be pulled from the wall "within arms reach".

C-Type days, standalone strobes can be a few hundred mA.

Long straight run with drops, catenary could be an option.

I'd nail the fixing band if I had a nailer. Spit nailer will do most surfaces, fixy band or metal ties size is adjustable to the job. The cable staples are timber only, one at a time, nice if you are just in bungalows maybe?

Fixy band?

The system will still rearm regardless, the number of times its programmed for. You just don't have the strobe flashing all the time until you get to site.

Where are you thinking of?

If your concerned about current look at the specifications of the output and what the device will pull, but would expect it to be fine.

Don't use Galaxy much but it's just what the default programming is IIRC. 1=Bell 2=Strobe, you could use whichever they are programmable. A dry relay with only one wire isn't connecting to anything on contact changeover. FWIW I would also use "bell follow" type output for strobe, to cancel the strobe with the bell like above.

Find of mine has a T72, as above I wouldn't use it enough. Also looks a bit bulky for awkward spaces.