Bypass Mechanism For V.34 Fax Transmission - AudioCodes Mediant 800B User Manual

User's Manual
To configure whether to pass V.34 over T38 fax relay, or use Bypass over the High Bit
Rate coder (e.g. PCM A-Law), use the 'V.34 Fax Transport Type' parameter
(V34FaxTransportType).
You can use the 'SIP T.38 Version' parameter (SIPT38Version) in the Advanced
Parameters page (Configuration tab > VoIP menu > SIP Definitions > Advanced
Parameters) to configure one of the following:

Pass V.34 over T.38 fax relay using bit rates of up to 33,600 bps ('SIP T.38 Version' is
set to Version 3).

Use Fax-over-T.38 fallback to T.30, using up to 14,400 bps ('SIP T.38 Version' is set
to Version 0).
Note:
CNG detector, set the 'CNG Detector Mode' parameter (CNGDetectorMode) to
Disable.

14.2.3.1 Bypass Mechanism for V.34 Fax Transmission

In this proprietary scenario, the device uses bypass (or NSE) mode to transmit V.34 faxes,
enabling the full utilization of its speed.

To use bypass mode for T.30 and V.34 faxes:
1. In the Fax/Modem/CID Settings page, do the following:
a. Set the 'Fax Transport Mode' parameter to Bypass (FaxTransportMode = 2).
b. Set the 'V.22 Modem Transport Type' parameter to Enable Bypass
(V22ModemTransportType = 2).
c. Set the 'V.23 Modem Transport Type' parameter to Enable Bypass
(V23ModemTransportType = 2).
d. Set the 'V.32 Modem Transport Type' parameter to Enable Bypass
(V32ModemTransportType = 2).
e. Set the 'V.34 Modem Transport Type' parameter to Enable Bypass
(V34ModemTransportType = 2).
2. Set the ini file parameter, V34FaxTransportType to 2 (Bypass).

To use bypass mode for V.34 faxes, and T.38 for T.30 faxes:
1. In 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 Enable Bypass
(V22ModemTransportType = 2).
c. Set the 'V.23 Modem Transport Type' parameter to Enable Bypass
(V23ModemTransportType = 2).
d. Set the 'V.32 Modem Transport Type' parameter to Enable Bypass
(V32ModemTransportType = 2).
e. Set the 'V.34 Modem Transport Type' parameter to Enable Bypass
(V34ModemTransportType = 2).
2. Set the ini file parameter, V34FaxTransportType to 2 (Bypass).
Version 6.8
The CNG detector is disabled in all the subsequent examples. To disable the
177 Mediant 800B Gateway and E-SBC
14. Media