In contrast to many other SIP programs that support voice telephony only, VentaFax when used as a SIP software client supports fax reception and transmission in both T.38 and G.711 "pass through" modes. Depending on the SIP server capabilities, it uses either T.38 real-time fax standard (preferred) or G.711 codec (where the fax data is encoded as audio) to transfer a fax within SIP telephony.
You may download and install VentaFax & Voice in order to try faxing through the SIP server before you buy it.
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