How are faxes sent and received in Genesys Cloud?

When a user sends a fax, Genesys Cloud converts the file to TIF file format and sends it to an Edge device. The Edge can be either onsite (BYOC Premises) or in the cloud (BYOC Cloud or Genesys Cloud Voice).

The Edge then sends the file to the user-entered number using your SIP trunks. If the file did not originate in Documents, Genesys Cloud also stores the original file in its original format in the user’s workspace in Documents. For information about how to send a fax from Genesys Cloud, see Send a fax.

Since a user has the same number for both incoming calls and faxes, the Edge must detect whether an incoming call is a voice call or fax. If fax detection is enabled and the Edge detects incoming fax tones, it negotiates the T.30 transmission, receives the image data, and sends the file to Genesys Cloud in TIF format. Genesys Cloud then converts the TIF file to a PDF file and sends it to both the user’s inbox and workspace in Documents. For information about how to view received faxes in Genesys Cloud, see View faxes in the inbox.

Genesys Cloud transmits faxes using T.30 protocols with a maximum transmission rate of 14.4k. The trunks carrying faxes should use audio/PCMU (G.711) as their primary codec. For more information about configuring a trunk and setting the codec, see About trunks.