Hi
I wanted to know the purpose of USB port in 750GR3. Can I plug any USB to Etnernet card in it to make another LAN interface ?
It can be used for storage and USB-LTE devices so theoretically a LAN adapter might also be possible (beware, no Gb speeds on Hex).
Provided the drivers are available…
This page (supported peripherals) shows supported drivers and I do see some ethernet stuff there.
https://help.mikrotik.com/docs/display/ROS/Peripherals
Here is recent thread where this was also discussed
http://forum.mikrotik.com/t/routeros-usb-ethernet-support/167781/1
You can also use USB as a serial port. All Mikrotik devices with a USB Port can display a console via USB.
Unfortuantely the OS has to start first for it to be available so you cannot use it to interrupt the boot process like a regular console port but it’s usefull nonetheless if you can’t access Winbox for some reason.
I use that with a 4G USB stick to have a backup for the main internet connection… but beware, it does not work with all sticks and all software versions.