Allied Telesis AT-IE300-12GP Installation Manual page 112

Chapter 6: Troubleshooting
Negotiation is connected to a remote device that has a fixed speed of 10
or 100 Mbps and a fixed duplex mode of full duplex. If this is the cause of
the problem, adjust the duplex mode of the port on the network device or
switch so that both ports are using the same duplex mode. For the AT-
IE300-12GT Switch, you can use either the LEDs or management
software on the switch to determine the duplex mode settings of the ports.
The LEDs are described in Table 7 on page 43. For the AT-IE300-12GP
Switch, you have to use the management software to determine the
duplex mode settings of the ports.
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