IP Office supports Avaya proprietary and T.38 fax transport protocols.
Avaya proprietary fax transport protocol
Fax calls route over VoIP trunks between IP Office systems on an IP network using a proprietary Avaya transport protocol.
T.38 fax transport protocol
IP Office supports the T.38 protocol for fax messages transmission between IP Office and SIP trunks and SIP extensions.
Platforms
IP500 V2 with a VCM32 or VCM64 module. Linux based Server Edition servers.
Trunk types
SIP
Extensions
SIP
Transport layers
UDPTL with optional redundancy error correction
Versions
0–3
Call types
Voice calls with transition to fax relay on detection of fax tones and calls which are negotiated as fax-only.
Fax fallback
SIP Trunks and SIP Extensions can now configure the Fax Transport Support to T38 Fallback so that outgoing fax calls use T.38 fax, but when the called destination doesn't support T.38 and rejects the call, a re-invite is sent for fax transport over G.711. Incoming audio calls that detect fax tones also initiate fax transport using T.38 Fallback. This allows IP Office to support additional deployments where T.38 fax may not be universally available.
