UNICOM Electric 8 - Manual (Page 26)

4-3-7. Misc Configuration
4-3-7-1. Port Security
A port in security mode will be locked without address learning
permission. Only the incoming packets with SMAC already existing in the
address table can be forwarded normally. Users can disable the port from
learning any new MAC addresses, then use the static MAC addresses
screen to define a list of MAC addresses that can use the secure port.
1. Press to enable or disable the port security.
2 Press Space key to choose Enable / Disable item