You can also send faxes via a SIP connection. To do this, your SIP provider must offer the T.38 standard used or G.711 by SwyxWare.

You will need to set up a dedicated SIP trunk, which is mapped to the SIP trunk group of this provider, but has the codec "Fax over IP (T.38, around 20 kbit/s per call)" ( The "Codecs/Channels" Tab).