Specifications

Interoperability Configuration Reference Manual (MGCP/NCS Version)
Mediatrix 4100
83
Fake RFC 3407 Recognition
You can allow the recognition of a remote endpoint's T.38 capabilities when they are advertised using the
notation recommended in RFC 3407. More precisely, when enabled, the Mediatrix 4100 will recognize the line
'a=cdsc: 1 image udptl t38' in the following SDP:
v=0
c=IN IP4 47.47.47.47
a=sqn: 0
a=cdsc: 1 image udptl t38
m=audio 1234 RTP/AVP 18
a=ptime:20
as valid T.38 support advertisement.
 To fake the RFC 3407 recognition:
1. In the mgcpncsExperimentalMIB, set the mgcpncsFakeRfc3407Recognition variable as required.
T.38 Negotiation Syntax
You can define the format used, in the SDP portion of SIP packets, to advertise the unit's T.38 capabilities.
 To set the T.38 negotiation syntax to use:
1. In the mgcpncsExperimentalMIB, set the mgcpncsUseItuT38Format variable with the proper
behaviour.
Note: No other part of the RFC is supported and the unit itself never uses this syntax.
Table 62: Modem Tone Reporting Parameters
Parameter Description
enable T.38 advertisement as described above is recognized
disable RFC 3407 syntax is ignored.
Standards Supported • ITU-T Recommendation T.38, section D.2.3
Table 63: T.38 Negotiation Syntax Usage
Parameter Description
disable Support for the boolean T.38 parameters T38FaxFillBitRemoval,
T38FaxTranscodingMMR, and T38FaxTranscodingJBIG is advertised by
associating a value of 0 (unsupported) or 1 (supported) with the parameter in the
following manner:
a=T38FaxFillBitRemoval:0
a=T38FaxTranscodingMMR:0
a=T38FaxTranscodingJBIG:0
This is the default value.
enable Support for the above T.38 parameters is advertised in conformance with ITU-T
Recommendation T.38, section D.2.3. The presence of the parameter in the SDP
indicates support for it (without the need for an associated value), while its absence
means that it is not supported.