3Com V7122 User Manual page 190

ini File Field Name
Web Parameter Name
TransparentCoderOnDataC
all
IsFaxUsed
[Fax Signaling Method]
T38UseRTPPort
190
Valid Range and Description
0 = Only use coders from the coder list (default).
1 = Use transparent coder for data calls (according to RFC 4040).
The 'Transparent' coder can be used on data calls. When the gateway
receives a Setup message from the ISDN with 'TransferCapabilities = data',
it can initiate a call using the coder 'Transparent' (even if the coder is not
included in the coder list).
The initiated INVITE includes the following SDP attribute:
a=rtpmap:97 CLEARMODE/8000
The default Payload Type is set according to the CoderName table. If the
Transparent coder is not set in the Coders table, the default value is set to
56. The Payload Type is negotiated with the remote side, that is, the
selected Payload Type is according to the remote side selection.
The receiving gateway must include the 'Transparent' coder in its coder list.
Determines the SIP signaling method used to establish and convey a fax
session after a fax is detected.
0 = No fax negotiation using SIP signaling (default).
1 = Initiates T.38 fax relay.
2 = Initiates fax using the coder G.711 A-law/μ-law with adaptations (see
note 1).
3 = Initiates T.38 fax relay. If the T.38 negotiation fails, the gateway re-
initiates a fax session using the coder G.711 A-law/μ-law with adaptations
(see note 1).
Fax adaptations:
Echo Canceller = On
Silence Compression = Off
Echo Canceller Non-Linear Processor Mode = Off
Dynamic Jitter Buffer Minimum Delay = 40
Dynamic Jitter Buffer Optimization Factor = 13
If the gateway initiates a fax session using G.711 (option 2 and
possibly 3), a 'gpmd' attribute is added to the SDP in the
following format:
For A-law: 'a=gpmd:0 vbd=yes;ecan=on'. For
vbd=yes;ecan=on'.
When 'IsFaxUsed' is set to 1, 2 or 3 the parameter
'FaxTransportMode' is ignored.
When the value of IsFaxUsed is other than 1, T.38 might still
be used without the control protocol's involvement. To
completely disable T.38, set FaxTransportMode to a value
other than 1.
Defines that the T.38 packets are sent / received using the same port as
RTP packets.
0 = Use the RTP port +2 to send / receive T.38 packets (default).
1 = Use the same port as the RTP port to send / receive T.38 packets.
μ
-law: 'a=gpmd:8
V7122 GatewayUser Guide