Key Considerations When Troubleshooting the Physical Fax Service

To ensure optimal fax machine performance, there are several settings that must be configured.

  • On the fax machine, please check the following settings:
    • Fax Speed or Baud Rate should be lowered to 9600bps.
    • Error Correction Mode (ECM) should be disabled.
    • Resolution should be Standard (not Fine, Ultrafine, Photo, etc.).
    • Overseas (International) Mode set to ON.
    • Set to Fax-Only mode.
  • Call Waiting must be disabled for the fax extension.
  • If you are using an MGCP BPA430 or similar adapter, prioritize port 15044 on the network.
  • If you are using a Cisco (Linksys) SPA 122 or 2102 adapter
Common Symptoms and Questions to Consider

Common Physical Fax Symptoms

  1. Unable to send or receive.
  2. Able to receive, but not able to send.
  3. Failure on first send attempt.
  4. Fax cut off.
  5. Cannot send to specific numbers.

Questions to Consider

  1. How long has the issue occurred?
  2. Does the failure occur on outbound, inbound, or both?
  3. Does it happen when dialing to a specific number or area code?
Troubleshooting Steps for Common Symptoms
Can Neither Send Nor Receive
  1. Check fax speed and baud rate on fax machine.
  2. Log in to the web GUI and ensure that the Preferred Codec is set to G.711 and T.38 is enabled.
  3. Check physical connections to and from the adapter.
    • Make sure the telephone cable is going from Line 1 on the adapter to Line 1 on the fax machine (unless you have a second port activation on your fax extensions).
    • Ensure the adapter is plugged into a valid Internet source.
  4. Check adapter-specific network settings.
  5. Attempt to set a static IP on the adapter.
  6. Make a test call to another fax number. You should hear fax tones. If it rings through as disconnected, proceed.
Cannot Send (Can Receive)
First Send Attempt Fails
  • Attempt to resend the fax.

First, check that all settings are properly configured as outlined above.

If the problem continues after proper configuration, and you are currently using an SPA 122 VoIP adapter, try swapping it for a BPA430 adapter.

If you cannot send faxes to specific numbers, please create a case with 8x8 Technical Support.