AudioCodes Mediant 800B - Relay Mode for T.30 and V.34 Faxes; Fax Relay for SG3 Fax Machines

Version 7.2 203 Mediant 800B Gateway & E-SBC
User's Manual 14. Media
14.2.3.2 Relay Mode for T.30 and V.34 Faxes
In this scenario, V.34 fax machines are forced to use their backward compatibility with T.30
faxes and operate in the slower T.30 mode.
 To use T.38 mode for V.34 and T.30 faxes:
1. On the Fax/Modem/CID Settings page, do the following:
a. Set the 'Fax Transport Mode' parameter to T.38 Relay (FaxTransportMode = 1).
b. Set the 'V.22 Modem Transport Type' parameter to Disable
(V22ModemTransportType = 0).
c. Set the 'V.23 Modem Transport Type' parameter to Disable
(V23ModemTransportType = 0).
d. Set the 'V.32 Modem Transport Type' parameter to Disable
(V32ModemTransportType = 0).
e. Set the 'V.34 Modem Transport Type' parameter to Disable
(V34ModemTransportType = 0).
2. Set the ini file parameter, V34FaxTransportType to 1 (Relay).
 To allow V.34 fax relay over T.38:

Set the 'SIP T.38 Version' parameter to Version 3 (SIPT38Version = 3).
 To force V.34 fax machines to use their backward compatibility with T.30 faxes
and operate in the slower T.30 mode:

Set the 'SIP T.38 Version' parameter to Version 0 (SIPT38Version = 0).
Note: Interworking of T.38 Version 3 is supported only for Gateway calls. For SBC
calls, the device forwards T.38 Version 3 transparently (as is) to the other leg (i.e., no
transcoding).
14.2.3.3 V.34 Fax Relay for SG3 Fax Machines
Super Group 3 (SG3) is a standard for fax machines that support speeds of up to 33.6
kbps through V.34 half duplex (HD) modulation. The following procedure describes how to
configure V.34 (SG3) fax relay support based on ITU Specification T.38 version 3.
 To enable support for V.34 fax relay (T.38) at SG3 speed:
1. In the IP Profiles table (see 'Configuring IP Profiles' on page 436), configure an IP
Profile with the 'Fax Signaling Method' parameter (IpProfile_IsFaxUsed) set to T.38
Relay.
2. In the Coder Groups table (see 'Configuring Coder Groups' on page 427) set the
coder used by the device to G.729 (or any other supported codec).
3. On the Fax/Modem/CID Settings page, do the following settings:
a. 'SIP T.38 Version' to Version 3 (SIPT38Version = 3).
b. 'Fax Relay Max Rate' (RelayMaxRate) to 33,600bps (default).
c. 'CNG Detector Mode' (CNGDetectorMode) to Disable (default).
d. 'V.21 Modem Transport Type' to Disable (V21ModemTransportType = 0).
e. 'V.22 Modem Transport Type' to Disable (V22ModemTransportType = 0).
f. 'V.23 Modem Transport Type' to Disable (V23ModemTransportType = 0).