Overview

Customers sometimes may experience issues with their e-fax service, where they only receive one page or partial pages of multi-page faxes from multiple numbers or a page header taking the place of a page footer instead. A SIP capture reveals no issues with the inbound faxes.

Solution

Most often, the issue is due to media configuration. While we offer multiple media codecs: G711 (PCMU & PCMA), t.38, the preferred media for e-fax is t.38.

When your trunk only accepts different media codec(s), the one that is used may be the root cause of the observed behavior. Reach out to your networking team or provider to set the preference list so that your trunk prioritizes t.38 for e-fax.

Summary

Incomplete or partial e-fax reception often results from incorrect media configuration, particularly when the wrong codec is used. The preferred codec for e-fax is t.38. Ensure that your trunk is configured to prioritize t.38 to resolve these issues.