The user can upgrade the device version in the ____________ interface.

The following four major components that are not air conditioners are ____________ .

The user can use the ____________ function to assign personnel to handle the fault.

UPS systematic N+X System ratio 2N The power supply guarantee level of the system is higher.

Protective grounding: Grounding refers to the direct connection with the earth, and a certain point of the live part of an electrical device or electrical circuit is connected to a large point. When the electrical device or other device is normal, a certain point of the uncharged part is artificially connected to the earth.