Continuing the discussion from Librem 5 media (photos and videos):
That’s pretty neat. The only one I’m regularly using is *100#, which seems to be non-standard, but retrieves my remaining pre-paid balance (AldiTalk).
I just thought it would be nice if some of those (standardized and custom) codes would be made available via UI. For example “temporary change of the transmission of CLIR” or “Change PIN”
I also use AldiTalk. The Pre Paid Manager (PPM) application made by Guido Günther also works with AldiTalk, can confirm that myself.
Works nice on the Librem 5. But the calls app also works now.
Ah, I had forgotten about that app 
Actually, sometimes I just used the USSD code because the AldiTalk-Android app takes half a minute to start on my Galaxy S3, so may be I won’t even really need that anymore on the Librem 5 
That is something I always refused to have. When I bought the card and went home, I flipped out that to activate it I would have to do a video conference with a AldiTalk employee to confirm my identity (that my face matched the one in the ID documents I would have to upload to a website).
I went back to the store and asked to activate the card there. The shop employees where like: really?!? you don’t wanna do this at home? We have other tasks to do…
When I bought mine, video activation was not a thing, luckily
As someone that comes from a country where you can just buy a pre paid SIM in pretty much any store, no questions asked, you can imagine my reaction. In the end I was able to activate the AldiTalk card in the supermarket.
Here is link to approach that already works with *100# over Calls UI, as just installed mobian-ussd-install.sh over wget and tested it as 100% reliable on my PinePhone. And, might be that we already have an (relatively) easy solution here: https://lipkowski.be/z/www/?&brain_id=61, same to here related video posted from @dos few days ago, or at least very similar (in purpose and content).
Fun fact about the PPM app linked above it was originally designed for laptops. So you can use it with your USB modem or built in modem.
Also the latest version of calls now supports USSD, so these very helpful temporary helper bash scripts, should no longer be necessary.