When connecting Polycom VVX 300 and VVX 400 phones to a gigabit network, the phone does not connect. The phones may display "Line Unregistered," and the time and date are out of sync.


Polycom VVX 300 and VVX 400 phones are not rated to gigabit speed, so they cannot use that connection speed. These phones are designed to auto-negotiate, but this does not always happen.

Note: If the phone gets a DHCP IP address, this is a separate issue.


To change both LAN port and PC port speeds to 100 FD (full duplex)

  1. On the phone, go to Menu > Settings.
  2. Select Advanced.
  3. Enter password.
  4. Select Administration Settings.
  5. Select Network Configuration > Ethernet Menu.
  6. Scroll down and select LAN Port Mode.
  7. For the Speed Setting, select 100FD (100 mbps Full Duplex).
  8. Go back to the Ethernet Menu and select PC Port Mode.
  9. For the Speed Setting, select 100FD.
  10. Return to the main menu. You will be prompted to Save the configuration and reboot the phone.