Configure Fax Voip FSP with VoIP Service Providers
When sending and receiving faxes over VoIP, it is strongly recommended to use VoIP service providers with T.38 support. T.38 - the most reliable standard used to transmit faxes over VoIP in real time. Isolates from the delays, timing jitter, and packet loss experienced in VoIP networks.
Below you will find examples of VoIP (SIP) providers that support T.38:
With Fax Voip FSP you also can send/receive audio faxes (fax over G.711 codec). This can be used with VoIP providers that don't support T.38 but provide good-quality voice channel. See example below: