Supported GSM Modems for US AT&T

I have been having difficulty getting a GSM modem working with the ServersCheck monitoring appliance. I have tried using the Huawei E8372h-608 USB modem and using AT&T Velocity USB Stick (MF861) without success. The reason why both of these modems aren't working with ServersCheck is because they are not in a GSM modem mode. There is no COM port associated with both of these devices.

What modems have been confirmed to work with ServersCheck that will also work with US AT&T cell service? I have seen that the Huawei E3276 may work but I want to find out for sure before I purchase the Huawei E3276.

You need a Huawei modem that creates a COM port on your computer. The MF861 is a ZTE modem / not Huawei. It seems that your Huawei E8372h modem is locked.

See this:
https://routerunlock.com/how-to-unlock-huawei-e8372h-153-and-e8372h-608-wingle/

Thank you for the link. Since we returned the Huawei E8372h-608 we have ordered the Huawei E3276 and will try it out once it arrives.

My Huawei E3276 also doesn't have COM ports. it is a STC HI LINK Huawei E3276.

JoemariSevilla ask your operator to unlock the modem so that the COM port feature is available