Why do VoIP calls not succeed over the GPRS/3G connection?

The VoIP connection over 3G or GPRS may fail if the VoIP service settings prohibit the use of VoIP over 3G and GPRS connections. The VoIP connections are in that case possible only over WLAN.

If the SIP VoIP Settings application has been installed in the device, the VoIP access over 3G and GPRS can be enabled in the following way:

  1. Depending on the device, go to:
    1. Menu > Tools (or Settings or Ctrl. panel) > Connectivity > Net settings > Advanced VoIP settings > VoIP services.
    2. Menu > Ctrl. panel > Net settings > Advanced VoIP settings > VoIP services.
    3. Menu > Settings > Connectivity > Admin.settings > Net settings > Advanced VoIP settings > VoIP services.
  2. Open the VoIP service profile and enter the Profile settings menu.
  3. Set AWCDMA = On.

When the AWCDMA setting is enabled, the VoIP connections can be established both over WLAN and 3G/GPRS networks.