Questions about Huawei E3531

According to https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=109052, the E3531 can be used with the Raspberry. According to https://www.datenreise.de/raspberry-pi-sms-per-kommandozeile-versenden/, SMS can also be sent via UMTS stick. However, direct compatibility for the Raspberry or Linux in general is not given, know-how is required for this and one must ensure that the stick is not recognised as a removable data carrier (driver installation) as under Win and Mac, but directly as a modem. This is explained under the link above. For sending SMS, the Gammu SMS Daemon is used in the instructions. Unfortunately, we cannot give any guarantee...

I got the E3531i-2. But it's been a long time since I got it.

Yes, that works.

The stick is compatible with the TL-MR3020.