User's Manual
Coders), set the coder used by the device to G.729 (or any other supported codec).
Note:
for DSP Template 10.
4.
On the Fax/Modem/CID Settings page, do the following settings:
a.
'SIP T.38 Version' to Version 3 (SIPT38Version = 3).
b.
'Fax Relay Max Rate' (RelayMaxRate) to 33,600bps (default).
c.
'CNG Detector Mode' (CNGDetectorMode) to Disable (default).
d.
'V.21 Modem Transport Type' to Disable (V21ModemTransportType = 0).
e.
'V.22 Modem Transport Type' to Disable (V22ModemTransportType = 0).
f.
'V.23 Modem Transport Type' to Disable (V23ModemTransportType = 0).
g.
'V.32 Modem Transport Type' to Disable (V32ModemTransportType = 0).
h.
'V.34 Modem Transport Type' to Disable (V34ModemTransportType = 0).
i.
'CED Transfer Mode' to Fax Relay or VBD (CEDTransferMode = 0). (Applicable
only to the Gateway application.)
5.
Set the ini file parameter, V34FaxTransportType to 1 (i.e., relay).
6.
Set the ini file parameter, T38MaxDatagramSize to 560 (default).
Notes:
•
The T.38 negotiation should be completed at call start according to V.152
procedure (as shown in the INVITE example below).
•
T.38 mid-call Re-INVITEs are supported.
•
If the remote party supports only T.38 Version 0, the device "downgrades" the
T.38 Version 3 to T.38 Version 0.
For example, the device sends or receives the following INVITE message, negotiating both
audio and image media:
INVITE sip:2001@10.8.211.250;user=phone SIP/2.0
Via: SIP/2.0/UDP 10.8.6.55;branch=z9hG4bKac1938966220
Max-Forwards: 70
From: <sip:318@10.8.6.55>;tag=1c1938956155
To: <sip:2001@10.8.211.250;user=phone>
Call-ID: 193895529241200022331@10.8.6.55
CSeq: 1 INVITE
Contact: <sip:318@10.8.6.55:5060>
Supported: em,100rel,timer,replaces,path,resource-priority,sdp-
anat
Allow:
REGISTER,OPTIONS,INVITE,ACK,CANCEL,BYE,NOTIFY,PRACK,REFER,INFO,SUB
SCRIBE,UPDATE
Remote-Party-ID:
<sip:318@10.8.211.250>;party=calling;privacy=off;screen=no;screen-
ind=0;npi=1;ton=0
Remote-Party-ID: <sip:2001@10.8.211.250>;party=called;npi=1;ton=0
User-Agent: Audiocodes-Sip-Gateway-/v.6.80A.227.005
Content-Type: application/sdp
Content-Length: 433
v=0
o=AudiocodesGW 1938931006 1938930708 IN IP4 10.8.6.55
Version 7.0
See SBC and DSP Channel Capacity on page 1061 to check the coder support
207
15. Media
Mediant 3000