Optimize Fax Completion Rates
Issues can occur with fax transmissions over IP networks, even with the T.38 standard. Use the following task to help avoid any issues.
Procedure
Step 1 |
Ensure that you have enough bandwidth for the uplink and the downlink.
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Step 2 |
Click Voice in the menu bar, and then click Line 1 or Line 2 in the navigation tree. |
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Step 3 |
In the Network Settings section, enter the following settings:
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Step 4 |
In the Supplementary Service Subscription section, enter the following settings:
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Step 5 |
In the Audio Configuration section, enter the following settings to support T.38 fax:
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Step 6 |
Click Submit to save your settings or click Cancel to abandon the unsaved settings. |
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Step 7 |
If you are using a Cisco media gateway for PSTN termination, disable T.38 (fax relay) and enable fax using modem passthrough. For example: modem passthrough nse payload-type 110 codec g711ulaw fax rate disable fax protocol pass-through g711ulaw
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Step 8 |
If you are using a Cisco media gateway, make sure that the Cisco gateway is correctly configured for T.38 with the dial peer. For example: fax protocol T38 fax rate voice fax-relay ecm disable fax nsf 000000 no vad |
Troubleshoot Your Fax
If you have problems sending or receiving faxes, complete the following steps:
Procedure
Step 1 |
Verify that your fax machine is set to a speed between 7200 and 14400. |
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Step 2 |
Send a test fax in a controlled environment between two ATAs. |
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Step 3 |
Determine the success rate. |
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Step 4 |
Monitor the network and record the statistics for jitter, loss, and delay. |
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Step 5 |
If faxes fail consistently, capture a copy of the configuration. You can then send this file to Technical Support. |
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Step 6 |
To enable logging, go to the System. page, and set the IP address of your syslog or debug server. Set the Debug Level to 3. For more information, see
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Step 7 |
Identify the type of fax machine connected to the ATA. |
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Step 8 |
Contact technical support:
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