AudioCodes Mediant 600 User Manual page 708

Parameter
EMS: NSE Payload Type
[NSEPayloadType]
EMS: T38 Use RTP Port
[T38UseRTPPort]
Web/EMS: T.38 Max Datagram
Size
[T38MaxDatagramSize]
Web/EMS: T38 Fax Max Buffer
[T38FaxMaxBufferSize]
Web: Detect Fax on Answer
Tone
EMS: Enables Detection of
FAX on Answer Tone
[DetFaxOnAnswerTone]
Web: T38 Fax Session
User's Manual

This feature can be used only if the VxxModemTransportType
parameter is set to 2 (Bypass).

If NSE mode is enabled, the SDP contains the following line:
'a=rtpmap:100 X-NSE/8000'.

To use this feature:

The Cisco gateway must include the following definition:
'modem passthrough nse payload-type 100 codec
g711alaw'.

Set the Modem transport type to Bypass mode
(VxxModemTransportType is set to 2) for all modems.

Configure the gateway parameter NSEPayloadType = 100.

This parameter can also be configured in an IP Profile.
Defines the NSE payload type for Cisco Bypass compatible mode.
The valid range is 96-127. The default is 105.
Note: Cisco gateways usually use NSE payload type of 100.
Defines the port (with relation to RTP port) for sending and
receiving T.38 packets.

[0] = (Default) Use the RTP port +2 to send/receive T.38
packets.

[1] = Use the same port as the RTP port to send/receive T.38
packets.
Notes:

For this parameter to take effect, you must reset the device.

When the device is configured to use V.152 to negotiate audio
and T.38 coders, the UDP port published in SDP for RTP and
for T38 must be different. Therefore, set the T38UseRTPPort
parameter to 0.
Defines the maximum size of a T.38 datagram that the device can
receive. This value is included in the outgoing SDP when T.38 is
used.
The valid range is 120 to 600. The default is 238.
Defines the maximum size (in bytes) of the device's T.38 buffer.
This value is included in the outgoing SDP when T.38 is used for
fax relay over IP.
The valid range is 500 to 3000. The default is 1024.
Determines when the device initiates a T.38 session for fax
transmission.

[0] Initiate T.38 on Preamble = (Default) The device to which
the called fax is connected initiates a T.38 session on receiving
HDLC Preamble signal from the fax.

[1] Initiate T.38 on CED = The device to which the called fax is
connected initiates a T.38 session on receiving a CED answer
tone from the fax. This option can only be used to relay fax
signals, as the device sends T.38 Re-INVITE on detection of
any fax/modem Answer tone (2100 Hz, amplitude modulated
2100 Hz, or 2100 Hz with phase reversals). The modem signal
fails when using T.38 for fax relay.
Note: This parameters is applicable only if the parameter
IsFaxUsed is set to 1 (T.38 Relay) or 3 (Fax Fallback).
Enables fax transmission of T.38 "no-signal" packets to the
708
Mediant 600 & Mediant 1000
Description
Document #: LTRT-83313