Allied Telesis AT-S80 - Manual (Page 58)

Chapter 4: Port Configuration
58 Section I: Using the Menus Interface
mismatch if the end node is operating at a fixed duplex mode of
full-duplex. To avoid this problem, disable Auto-Negotiation on the
port and set the port’s speed and duplex mode manually when
connecting an end node with a fixed duplex mode of full-duplex to
a switch port.
ˆ For 1000 Mbps operation on an uplink 10/100/1000Base-T twisted
pair uplink port, Allied Telesis recommends using Auto-
Negotiation. Setting the speed and duplex mode manually to 1000
Mbps full duplex is not recommended.
ˆ The only valid setting for an optional SFP port is Auto-Negotiation.
6. Type Q to select Quit to previous menu and save your changes.