Some modems, specifically the 3Com Ethernet-only model 3CR29220, register on the cable network but the PC is unable to connect to the Cable Modem.

Check the PC's IP address:
To check for IP configuration on the PC, use the winipcfg command.

Check the cable modem's serial number:
To verify your modem's status, check to see if your modem serial number ends with the letters 'AO.' If your serial number ends in 'AO,' your modem should not be affected and no further action is necessary. If you do not see an 'AO,' you will need to install a POLARITY CHANGE ETHERNET CABLE. This cable is available from 3Com.

**This issue does not affect existing modems that have been deployed and are already working with an installed NIC. However, this issue could occur if the NIC in the PC is replaced and the PC cannot get an IP address as a result of that change.