AudioCodes E-SBC User Manual

CHAPTER15 Media
Mediant 1000 Gateway & E-SBC | User's Manual
2. On the Fax/Modem/CID Settings page, do the following:
● Set the 'Fax Transport Mode' parameter to Bypass (FaxTransportMode = 2).
● Set the 'V.21 Modem Transport Type' parameter to Enable Bypass
(V21ModemTransportType = 2).
● Set the 'V.22 Modem Transport Type' parameter to Enable Bypass
(V22ModemTransportType = 2).
● Set the 'V.23 Modem Transport Type' parameter to Enable Bypass
(V23ModemTransportType = 2).
● Set the 'V.32 Modem Transport Type' parameter to Enable Bypass
(V32ModemTransportType = 2).
● Set the 'V.34 Modem Transport Type' parameter to Enable Bypass
(V34ModemTransportType = 2).
3. Set the ini file parameter, BellModemTransportType to 2 (Bypass).
4. Configure the following optional parameters:
● 'Fax/Modem Bypass Coder Type' (FaxModemBypassCoderType).
● 'Fax Bypass Payload Type' (FaxBypassPayloadType).
● ModemBypassPayloadType (ini file).
● FaxModemBypassBasicRTPPacketInterval (ini file).
● FaxModemBypasDJBufMinDelay (ini file).
● When the device is configured for modem bypass and T.38 fax, V.21 low-speed
modems are not supported and fail as a result.
● When the remote (non-AudioCodes) gateway uses the G.711 coder for voice and
doesn’t change the coder payload type for fax or modem transmission, it is
recommended to use the Bypass mode with the following configuration:
✔ EnableFaxModemInbandNetworkDetection = 1.
✔ 'Fax/Modem Bypass Coder Type' = same coder used for voice.
✔ 'Fax/Modem Bypass Packing Factor'(FaxModemBypassM) = same interval as
voice.
✔ ModemBypassPayloadType = 8 if voice coder is A-Law or 0 if voice coder is
Mu-Law.
Fax / Modem NSE Mode
In this mode, fax and modem signals are transferred using Cisco-compatible Pass-through bypass
mode. Upon detection of fax or modem answering tone signal, the terminating device sends three
to six special NSE RTP packets (configured by the NSEpayloadType parameter; usually to 100).
These packets signal the remote device to switch to G.711 coder, according to the 'Fax/Modem
Bypass Packing Factor' parameter. After a few NSE packets are exchanged between the devices,
both devices start using G.711 packets with standard payload type (8 for G.711 A-Law and 0 for
G.711 Mu-Law). In this mode, no Re-INVITE messages are sent. The voice channel is optimized
for fax/modem transmission (same as for usual bypass mode).
The following parameters that configure the payload type for the AudioCodes proprietary Bypass
mode are not used with NSE Bypass: 'Fax Bypass Payload Type' and
[ModemBypassPayloadType].
When configured for NSE mode, the device includes the following line in the SDP, where 100 is the
NSE payload type:
a=rtpmap:100 X-NSE/8000
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AudioCodes E-SBC Specifications

General

Brand	AudioCodes
Model	E-SBC
Category	Gateway
Language	English