The fax feature is another paid feature that gives you a full fax-to-e-mail server using the standard T.38 fax format. The gateway line must also support T.38. Most VoIP providers do not support faxing, so check with them before signing up if this is a needed option.
When a fax comes into 3CX, it goes to the fax server portion of the system. It will convert the fax into a PDF and then e-mail it to the fax recipient.
You will need a dedicated line to use as a fax line, or you can set up a DID as a fax line over the same VoIP line (using a dedicated number for a fax).
To set this up you will need to specify a DID line, like we did earlier in this chapter. Only now, we need to specify the rule to the Send fax to email of extension field. You can use the 888 Default FAX Destination, or you can use the e-mail of any extension you have created for dedicated fax lines:

If you would like to change the fax server e-mail address, go to Settings | Fax. This will bring you to the screen...