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CallTower Solutions Center

Cisco 79XX - Troubleshooting Cisco 7942 Or 7962 VPN Phone


The purpose of this article is to help users understand how to troubleshoot a Cisco 7942 or 7962 VPN enabled phone and educate on how these phones are configured and connect.


Register the phone on a hosted voice connection

•    The phone first needs to be registered on a hosted provided voice connection if this has not or cannot be done the phone may need to be sent to a site that has this connection or replaced.
•    Once the phone has registered on the voice connection, you may plug the phone into any normal data internet connection.

Verify VPN is enabled

  1. On the phone press the “Settings” button
  2.  Select “Security Configuration” (option 4)
  3.  Select “VPN Configuration” (option 8)
  4.  Option 1 should be enabled
    4.1 If option 1 is disabled select the “Enable” soft key at the bottom of the screen.

Clear the CTL and ITL Security Files

  1. On the phone press the “Settings” button 
  2. Select “Security Configuration” (option 4)
  3. Select “Trust List” (option 5)
  4. CTL file (option 1) should read “Not Installed” & ITL File (option 2) should read “Not Installed”. 
  5. If either of these shows anything other than “Not Installed”: 
  6. Press **# to unlock the settings
  7. Select the file using the “Select” soft key
  8. Press “Unlock” using the soft key
  9. Press the “More” soft key
  10. Select the “Erase” soft key

Verify the TFTP Settings on the Phone

  1. On the phone press the “Settings” button
  2. Select the option “Network Configuration” (option 2)
  3. Select “IPv4 Configuration” (option 1)
  4. Scroll to “Alternate TFTP” (option 16) and it should read “Yes”
  5. Scroll to the “TFTP Server 1” (option 17) and it should read “<client TFTP server IP>”
  6. If the “Alternate TFTP” is set to “No” or “TFTP Server 1” is incorrect:
  7. Press **# to unlock the settings
  8. Highlight “Alternate TFTP” (option 16)
  9. Press the soft key labeled “Yes”
  10. Scroll to “TFTP Server 1” (option 17)
  11. Press the soft key labeled “Edit”
  12.  In the new screen enter “<client TFTP server IP>”
  13. Press the “Validate” soft key
  14. Press the “Save” soft key
  15. The phone may reset itself after these changes

Additional Information/Troubleshooting Steps  

  • If VPN authentication fails, press the “Retry” soft key (you may need to press this button multiple times).
  • If the phone still fails to connect after multiple times, unplug the phone so that it powers completely off, then plug it back in and try to connect again.

Contact Support

  • If the problem persists, or TFTP server information is needed after multiple attempts contact the support team for further assistance by calling 800-347-5444 or emailing  You can also chat with CallTower Support by visiting and selecting "LIVE CHAT" at the bottom right hand of the page.
    • Please provide the following information to the CallTower Support Technician:
      • MAC Address of the phone.
      • Name of the user of the phone.
    • This information will assist in arriving at a quicker resolution.
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