I got some extra SIM cards for my account and tried them on different modems. The Huawei USB WiFi router works without problems. I expected that it would be a classic LTE modem. I tried sending an SMS using AT command via Teltonika LTE 4g modem (model TRM240), but it didn’t work. Does anyone have experience with AT commands on a modem with a Sunrise SIM card? Is there any restriction for an extra SIM card?