System information

APPENDIX H. TROUBLESHOOTING VOIP H-9
If you are using a board with its own NIC interface, use the IP address of the board, not
of the TeleVantage Server itself.
Q Ensure that a supported codec and frame size are in use. Only G.711 is supported
with the Uniden IP phone. Other codecs have received limited testing. Make sure the
frame size is set to the same value in TeleVantage and the Uniden phone. The Uniden
phone defaults to 20 ms frames and TeleVantage defaults to 20ms or 30 ms. Polycom
phones support G.711 and G.723 codecs when used with TeleVantage and IP phones.
Q Confirm that there is an available IP trunk. If IP phone users share IP trunks on the
TeleVantage Server, there may be no IP trunks available at the time they are trying to
make a call. This can be confirmed by observing the state of the IP trunks in the
TeleVantage Device Monitor.
Q Check the network. You may be experiencing a network problem. Make sure you can
ping the IP address of the IP telephony board or TeleVantage Server.
Q Check the H.323 stack. If users see “Disconnected” in the LCD screen of the IP phone,
there may be a problem with the IP telephony board or its H.323 stack. Check the
Windows server event log to verify errors. The IP telephony board or TeleVantage
Server may need to be restarted.
If you are using the Tftpd32 TFTP Server (included with TeleVantage) to download updates to
Polycom or Uniden H.323 phones’ firmware and configuration files, your Technical Support
representative may ask you to turn on Tftpd32 TFTP Server logging via the Windows registry setting
TftpLogFile. To do so, see page J-16. For more about the Tftpd32 TFTP Server, see Chapter 17.
Testing audio delay from an IP phone with *18
You can press *18 from dial tone at an IP phone to test the phone’s connection to the
TeleVantage Server. After you press
*18, the system echoes back anything you say, enabling
you to judge any delay occurring between the phone and TeleVantage. To end the test, hang up
or press
#.
This test can help you judge whether poor audio quality is occurring between the phone and
TeleVantage, or elsewhere in the Internet connection.