Occupancy power supply Huawei S7-310u?

Bl
1

My power supply for the above device is broken. What is the pin assignment? So which of the two tiller is + and which -? Since it is a DC power supply, I can't solder this arbitrarily.

Mi

Plus is usually inside with female connectors, minus on the outside.

But would have to be an icon next to the socket such as - (+