Diagnosing "NO CARRIER" messages
The output from ifconfig is showing that eth0 has "NO CARRIER". Every physical link in an Ethernet network has a carrier signal present at all times, even if no data are flowing. For example, if you were to plug a network cable between an EAM and an Ethernet switch, there would be a carrier signal on that physical link - the cable - even if there were no other devices on the "network".If an interface reports "NO CARRIER", it means that the interface is not connected to another functioning interface or that it is itself broken. There are several things to try:
- Is the cable physically connected properly? Are the connectors pushed fully home?
- Is the cable connected directly to laptop or PC rather than a switch or router? If so, it is possible that the laptop/PC doesn't implement auto MDI-X. Verify this by connecting the EAM to switch or router rather than a PC or laptop. If this does prove to be the problem, you can use an Ethernet crossover adapter (such as this) or order an Ethernet crossover cable from us. The part number is CAS-DCM-0025.
- Try connecting the cable to a different port on the switch (where possible) or to a different switch. Individual switch ports can become blocked so using a different one may resolve the problem. If this works, power-cycling the switch usually unblocks the offending port; if not, there is a hardware problem with the switch.
- If possible, verify that the switch port (or other partner interface) is working correctly by connecting a different device, such as a laptop, in place of the EAM.
- Try using a different network cable: a damaged cable can give rise to these symptoms.
If all of these tests fail, there is a hardware problem with the EAM. Please contact for advice.