Comment by biktor_gj

It has had different phone numbers before, but we always ended up having some issue with some app where the it (correctly) thought the number was invalid, wouldn't allow you to reply etc.

So I settled with two easy to remember numbers: +22 33 44 55 66 77 for normal user<-->modem communication and +22 33 44 55 66 78 for Cell Broadcast message relays