Supporting V.34 Faxes; Using Bypass Mechanism For V.34 Fax Transmission; Using Relay Mode For Both T.30 And V.34 Faxes - AudioCodes Mediant 2000 User Manual

Mediant Series and TP-1610 H.323 User's Manual
FaxModemBypassM configuration parameter. The network packets to be generated and received
during the bypass period are regular voice RTP packets (per the selected bypass coder) but with
a different RTP Payload type.
When fax/modem transmission ends, the reverse is carried out, and bypass coder is switched to
regular voice coder.
8.3.4

Supporting V.34 Faxes

V.34 faxes don't comply with the T.38 relay standard. We therefore provide the optional modes
described under Sections
Note that the CNG detector is disabled (CNGDetectorMode=0) in all the following examples.
8.3.4.1

Using Bypass Mechanism for V.34 Fax Transmission

In this proprietary scenario, the media gateway uses a high bit-rate coder to transmit V.34 faxes,
enabling the full utilization of its speed.
Refer to the following configurations:
FaxTransportMode = 2 (Bypass)
V34ModemTransportType = 2 (Modem bypass)
V32ModemTransportType = 2
V23ModemTransportType = 2
V22ModemTransportType = 2
In this configuration, both T.30 and V.34 faxes work in Bypass mode.
Or
FaxTransportMode = 1 (Relay)
V34ModemTransportType = 2 (Modem bypass)
V32ModemTransportType = 2
V23ModemTransportType = 2
V22ModemTransportType = 2
In this configuration, T.30 fax uses T.38 Relay mode while V.34 fax uses Bypass mode.
8.3.4.2

Using Relay Mode for both T.30 and V.34 Faxes

In this scenario, V.34 fax machines are compelled to use their backward compatibility with T.30
faxes; as a T.30 machine, the V.34 fax can use T.38 Relay mode.
Refer to the following configuration:
FaxTransportMode = 1 (Relay)
V34ModemTransportType = 0 (Transparent)
V32ModemTransportType = 0
V23ModemTransportType = 0
V22ModemTransportType = 0
Both T.30 and V.34 faxes use T.38 Relay mode. This configuration forces the V.34 fax machine
to operate in the slower T.30 mode.
Version 4.6
8.3.4.1 and 8.3.4.2:
167
8. Telephony Capabilities
July 2005