HP 310X - Manual (Page 171)

Link lights OFF
for HP Jetdirect 175x external print server/Internet connector for USB
and HP Jetdirect 310x external print server/Internet connector for
USB
Try the steps below and make any necessary corrections.
Make sure that the network cable is connected securely to the
print server.
network cable
1.
Check that the network cable is plugged securely into the
hub/switch/router, and that the connection is set to the correct
network speed. (If your hub/switch/router is set to configure its
link speed automatically, try to configure it manually for 10
Mbps or 100 Mbps only. After changing this setting, you may
need to cycle power to the print server -- unplug the print
server's power cable and then plug it in again.) 2.
Check that the LINK light is ON for the port on the
hub/switch/router to which the print server is connected. 3.
Your network cable may be faulty. Try a different cable. 4.
If the light still does not come on, try a different port on the
hub/switch/router. 5.
Did these steps turn ON one of the link lights?
If yes, click on the Yes button to continue the troubleshooting
procedure.
If no, your print server has a problem that requires assistance from HP
Jetdirect technical support; click on the No button for a list of