Allied Telesis X610-24TS/X-POE+ User Manual

Page of 128
x610 Series Layer 3 Gigabit Ethernet Switches Installation Guide
113
Twisted Pair Port Link LED is Off
When a twisted pair port on the switch is connected to a properly operating 
end node, the Link LED for the port should be on. If a Link LED is off, do 
the following:
Note
A 1000Base-T connection can take from five to ten seconds to 
establish a link.
Verify that the end node connected to the port is powered ON and is 
operating properly.
Check that the twisted pair cable is securely connected to the port on 
the switch and to the port on the end node.
Make sure that the twisted pair cable does not exceed 100m (328 ft).
Verify that you are using the appropriate category of twisted pair cable. 
For information, refer to Table 17 on page 98.
Determine if a crossover cable is required. Since the twisted pair ports 
feature auto MDI/MDI-X, you should be able to use a straight-through 
cable regardless of the type of device you connect to a port. However, 
if you disable Auto-Negotiation on a port and set a port’s speed and 
duplex mode manually, the port defaults to MDI-X. Disabling Auto-
Negotiation may require manually configuring a port’s MDI/MDI-X 
setting or using a crossover cable.
Make sure that the operating parameters of a port on the switch are 
compatible with the end node to which the port is connected. This may 
require using the switch’s operating system software.
For a switch port to successfully Auto-Negotiate its duplex mode with 
an end node, the end node should also be using Auto-Negotiation. 
Otherwise, a duplex mode mismatch can occur. A switch port using 
Auto-Negotiation defaults to half-duplex if it detects that the end node 
is not using Auto-Negotiation. This can result in a mismatch if the end 
node is operating at a fixed duplex mode of full-duplex.
To avoid this problem, disable Auto-Negotiation on a switch port and 
set the port’s speed and duplex mode manually if the end node has a 
fixed duplex mode of full-duplex.
The switch has a bad cable detection feature that enables it to 
determine if a twisted pair cable has a electrical short that might cause 
a network loop. If the switch detects a bad cable on a port, it does not 
establish a link on that port. In this situation, replace the cable.