HP Jetdirect 250m Print Server series - Manual (Page 106)

12 LAN Error: NO LINKBEAT
When the print server is connected to a 10/100 Base-TX port, this message is displayed if the Link Beat
signal is not sensed.
Check the network cable, and verify that the hub/switch/router is providing Link Beat.
For help in correcting this error, please contact HP Jetdirect technical support. Click on the button below
for information on contacting HP.