No Voice

There are a number of possible causes for no voice/sound (in either one or both directions):

Volume setting

The speaker/microphone volume may be turned down – the volume can be increased from the Options->Phone Settings... form or by using the navigate up/down rocker (or scroll up/down).

On Treo devices, ensure that the sound switch at the top of the device is switched to on.

Silence suppression

Silence suppression saves network bandwidth by not transmitting when you are not speaking – it is possible that Articulation has incorrectly determined that you are not speaking and therefore is not transmitting. This can also cause problems with incoming voice as some systems do not send voice until they receive voice. To resolve this un-check Silence Suppression from the Options->Phone Settings... form.

Echo cancellation

Echo cancellation works by muting the microphone when voice is detected from the remote party – if the remote party is in a noisy environment it is possible that the echo cancellation is muting the microphone. To resolve this un-check Echo Cancellation from the Options->Phone Settings... form. Note that you should use a headset in this case otherwise the remote party may hear echo.

Blocked ports or Symmetric routers

Some routers/carriers that connect your PDA to the internet use a system known as Symmetric NAT. This system does not allow traversal of VoIP voice streams unless it is supported by your VoIP service provider or worked around with some manual configuration.

If you can hear voice using the Echo Test or Time Test options from the Call menu but cannot hear voice from your service provider then it is most likely that you have a Symmetric NAT router. In this case you will need to use port forwarding or find a VoIP service that provides Symmetric RTP or supports Symmetric routers (as the fwdnat.pulver.com:5082 service does).

To use port forwarding, you need to manually map ports on your router to the ports on your PDA. This means giving your PDA a static IP address on your network and performing the mapping of two public UDP ports on your router to ports 5060 and 5000 on your PDA. Refer to your router documentation for instructions on doing this.

Within Articulation, use Options->NAT Settings set the SIP port to the public port number that you have mapped to 5060 and the RTP port to the public port that you have mapped to 5000 (usually it is simplest to use 5060 and 5000 as the public ports as well as the mapped ports).

Often you will be able to leave the IP address empty on the NAT settings dialog. You can set this if you have a static IP address on the internet.