AudioCodes Mediant 2000, User Manual

Page: 71 / 418

Version 5.6 71 November 2008
SIP User's Manual 3. Web-Based Management
Parameter Description
Fax CNG Mode
[FaxCNGMode]
Determines the device's behavior upon detection of a
CNG tone.
ƒ
[0]
= Does not send a SIP Re-INVITE upon detection
of a fax CNG tone when CNGDetectorMode is set to
1 (default).
ƒ
[1]
= Sends a SIP Re-INVITE upon detection of a fax
CNG tone when CNGDetectorMode is set to 1.
CNG Detector Mode
[CNGDetectorMode]
Determines whether the device detects the fax Calling
tone (CNG).
ƒ
[0]
Disable = The originating device doesn’t detect
CNG; the CNG signal passes transparently to the
remote side (default).
ƒ
[1]
Relay = CNG is detected on the originating side.
CNG packets are sent to the remote side according
to T.38 (if IsFaxUsed = 1) and the fax session is
started. A Re-INVITE message isn’t sent and the fax
session starts by the terminating device. This option
is useful, for example, when the originating device is
located behind a firewall that blocks incoming T.38
packets on ports that have not yet received T.38
packets from the internal network (i.e., originating
device). To also send a SIP Re-INVITE message
upon detection of a fax CNG tone in this mode, set
the parameter FaxCNGMode to 1.
ƒ
[2]
Events Only = CNG is detected on the originating
side and a fax session is started by the originating
side using the Re-INVITE message. Usually, T.38 fax
session starts when the ‘preamble’ signal is detected
by the answering side. Some SIP devices don’t
support the detection of this fax signal on the
answering side and thus, in these cases it is possible
to configure the device to start the T.38 fax session
when the CNG tone is detected by the originating
side. However, this mode is not recommended.
T.38 Max Datagram Size
[T38MaxDatagram]
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 in use.
The valid range is 122 to 1,024. The default value is 122.