Can you record the current level using awk and alsamixer sget to a file, like the PID, just before you set it to 100. Then restore it when you do the cleanup up the end.

With this + a simple shell script, shouldn't it be possible to look for certain keywords in incoming mails, and sound an alarm if such are found?

I'm a little unsure if i can but i'll do my best. Right now, i have the problem that the terminal stops working after some time and i have to restart it. I have gotten one alarm now but i don't want to miss the next one. So- having the sound restored is somewhat the icing on the cake.

Sounds like OOM kills of terminal.

I see my terminal cover often greyed out, i.e. killed and the command just interrupted

I extended my swap manually with a swap file on home (maybe better on SD card like on N900?) and it got better.

Maybe try with ShellEx or qCommand from openrepos?

Or let a cron job restart this command every xx minutes?
(will you get re-notified more often via mail?)

Did a little digging. You can use alsamixer -sget Master but you may also be able to use alsactl.

Maybe something like editing the dbus command posted earlier to add

alsactl --file ~/.config/asound.state store

Before the alsamixer -sset Master bit and

alsactl --file ~/.config/asound.state restore

In the kill/cleanup part.

Sounds good, will try. But then the script worked very well twice today already. Which means that i'm really tired. Because it was quite early when my sleep was interrupted.

Cannot help you with this sound stuff,
as I am not really a knowledged one regarding PA, alsa and so on
and all that alsa vodoo just gives me a lot of 'no such device' or 'cannot read control' or similar on XA2...

No problem, you helped a great deal already. I just need some time to figure things out. As long as i have a working solution, i'm fine.

To dodge into a different direction may I ask what bulky analog device you have for callouts? Are people still using Motorola Minotaur and Minotaur IIs?(edit, damn they are up to the Minotaur 6, now as big as a little '90s belt pager now but still voice paging.)
I was a paid guy and finished as an officer and EMT-P but ended up taking the tech telated topics during my 8-5 work hours, though we were still doing in the VHF in rural western US when I medical'ed out.
I am also an amateur radio guy so hacking a VHF receiver with tone controls back then was cake though we also had commercial UHF POCSAG pagers with priority so they all beeped about 1-2 sec after the tones came over the VHF dispatch channel.
Not sure what your dispatch's setup looks like.

Big life altering advice for all first responders.
Lift properly, ask for help(hard for young guys, especially young volunteers), protect your spine, stairways with a patient on the cot and you are the backwards guy will get you; the damage you do might put you away fast or might just get worse over time; it is what ended my career.
Also remember that car drivers are what kill by far the most first responders and that people get lax at training events in a way they never would on a real call(hours of repeated extinguish/relight burn to learns especially).
Pass this on to the young guys at your department and wherever you end up doing teaching.

I guess today one could maybe do this with a cheap SDR USB stick and a Raspberry Pi.