Version 7.2 183 Mediant 1000B Gateway & E-SBC
User's Manual 14. Media
Echo Canceller = off
Silence Compression = off
Echo Canceller Non-Linear Processor Mode = off
Dynamic Jitter Buffer Minimum Delay = 40
Dynamic Jitter Buffer Optimization Factor = 13
After a few seconds upon detection of fax V.21 preamble or super G3 fax signals, the
device sends a second Re-INVITE enabling the echo canceller (the echo canceller is
disabled only on modem transmission).
A ‘gpmd’ attribute is added to the SDP according to the following format:
For G.711 A-law:
a=gpmd:0 vbd=yes;ecan=on (or off for modems)
For G.711 µ-law:
a=gpmd:8 vbd=yes;ecan=on (or off for modems)
The following parameters are ignored and automatically set to Events Only:
'Fax Transport Mode' (FaxTransportMode)
'Vxx ModemTransportType' (VxxModemTransportType)
To configure fax / modem transparent mode:
1. Open the Gateway General Settings page (Setup menu > Signaling & Media tab >
Gateway folder > Gateway General Settings), and then from the 'Fax Signaling
Method' drop-down list (IsFaxUsed), select G.711 Transport:
Figure 14-7: Configuring Fax Signaling to G.711
2. Click Apply.
14.2.2.3 Fax Fallback
In this mode, when the terminating device detects a fax signal, it sends a Re-INVITE
message to the originating device with T.38. If the remote device doesn’t support T.38
(replies with SIP response 415 "Media Not Supported"), the device sends a new Re-
INVITE with G.711 VBD with the following 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
When the device initiates a fax session using G.711, a ‘gpmd’ attribute is added to the SDP
according to the following format:
For G.711A-law:
a=gpmd:0 vbd=yes;ecan=on
For G.711 µ-law:
a=gpmd:8 vbd=yes;ecan=on
In this mode, the 'Fax Transport Mode' (FaxTransportMode) parameter is ignored and
automatically set to Disable (transparent mode).
To Next Page
Loading...
Need help?
General
