@billharz You can login to the web UI of the MR400 and verify whether there is an option to change the language of the system on the right upper corner. For the VPN issue, to build up the IPsec LAN...

@MDRAJU May I know who is the sim card carrier? And what kind of band aggregation it supports?

@sakis_s In 3G mode, the ethernet port will be the LAN port and you can connect your device to it by wired cable to get internet.

@MartiX By unplug the electrical appliance, we can reduce the powerline noise from these devices. You can give it a go and verify whether the speed gets better. While we cannot say that there won't...

@JD2019 For your information, Ethernet powerline adapter (Like TL-PA511) is made up of two parts: PIB and NVM. The firmware version number on the utility is actually the PIB version number, therefore...

@locomoto We only need connect one of the ethernet port to the main router by wired cable. Connected both LAN ports to the router by wired cable won't help to improve the speed. May it help.