3Com 3CR990-TX-97, 3CR990-TX-95, 3CR990SVR97, 3CR990SVR95 manual Troubleshooting a Network Connection

136CHAPTER 8: TROUBLESHOOTING THE NIC

5If the previous steps have failed, install a known functioning Remote Wake-Up NIC in the computer.

If Remote Wake-Up works with the new NIC installed, contact your computer vendor for a replacement NIC.

If Remote Wake-Up does not work with the new NIC installed, there may be a problem with the computer motherboard. Contact your computer manufacturer.

Troubleshooting a Network Connection

When working with 10BASE-T or 100BASE-TX cabling, concentrators, and NICs from different vendors, it

is possible to connect everything but still have no network communication.

For additional network troubleshooting information, see Running NIC Diagnostics on page 143.

To narrow the range of possible causes of common network connection problems:

1Determine whether your equipment complies with the 10BASE-T or 100BASE-TX standard.

This is particularly important for data concentrators (hubs or repeaters).

2Connect a straight-through cable from the PC to the hub.

The hub performs an internal crossover so that the signal can go from TD+ to RD+ and TD– to RD–. When you look at an RJ-45 connector from the front (that is, the opposite side from where the wires enter the connector), pin 1 is identified on the right side when the metal contacts are facing up.

3Make sure that the TD+ and TD– wires are twisted together, and that the RD+ and RD– are twisted together.

Using wires from opposing pairs can cause signals to be lost.