User`s manual

Table Of Contents
SIP User's Manual 8. Telephony Capabilities
Version 5.0 211 October 2006
8.3.1.3 Supporting V.34 Faxes
V.34 fax machine support is available only in bypass mode (fax relay is not supported)
when the channel is configured in one of the configurations described below:
FaxTransportMode = 2 (Bypass)
V34ModemTransportType = 2 (Modem bypass)
In this configuration, both T.30 and V.34 faxes work in Bypass mode
Or
FaxTransportMode = 1 (Relay)
V34ModemTransportType = 2 (Modem bypass)
In this configuration, T.30 faxes use Relay mode (T.38) while V.34 fax uses Bypass mode.
In order to use V.34 fax in Relay mode (T.38), you must configure:
FaxTransportMode = 1 (Relay)
V34ModemTransportType = 0 (Transparent)
V32ModemTransportType = 0
V23ModemTransportType = 0
V22ModemTransportType = 0
This configuration forces the V.34 fax machine to work in T.30 mode.