There are times and places when your BMS could wind up being 'uncontactable' and when there's a need to reset its network settings, or a need to reset the entire device back to 'factory defaults'. This includes (but is not limited to) situations where you've changed the network settings for the BMS and the settings turn out to be have been wrongly entered (or the network concerned has, in turn, changed details).
If you need to do this with the BMS, you just need plug in any old USB keyboard.
(If you had an HDMI screen plugged in, you'd actually see the following menu as well - but you don't need to do that - as you can 'navigate' entirely using sounds)
This is the BMS control menu that is provided (and controlled) by a USB keyboard:
rb : Reboot BMS
re : Reset Ethernet to DHCP
rw : Reset WiFi to Access Point mode
rf : Reset to factory default
ESC : Reset input
All you need to do, with the USB keyboard you've attached, is to type the two letter combination of your choice from the list above.
When you enter a valid key combination from that menu, you will hear a long beep from the BMS unit. That long beep is simply the BMS saying 'are you sure?'.
In response to the long beep, just type 'y' (for yes) and the action you have selected will be taken - and the BMS will reboot to make it so.
If you hear a quick double-beep instead, this means your input was not valid - and you should simply try again.