Filter
Top Products
VoIP profile configuration task list 589
SmartWare Software Configuration Guide 47 • VoIP profile configuration
Note The first codec must always be T.38, while the second one must be a high-
rate codec such as G.711, which supports fax transmission.
Configuring modem transmission
Modem transmission is similar to fax transmission, except that modem data is always transported in bypass
mode. This means that an ordered list of bypass codecs can be defined for modem transmission. If no modem
transmission codec is configured, no action is taken to change the codec when modem is detected.
Procedure: Configure modem bypass
Mode: Profile VoIP
Modem bypass method
This command specifies the method to be used for signaling the remote device the RTP Stream has switched to
a voice-band Modem transmission. This feature is only available on the SIP protocol. If the command option
v150-vbd is selected, a re-invite will be sent even if the current voice coder is configured the same as the
modem bypass coder. Furthermore the re-invite contains a gpmd-attribute line with the value vbd=yes;ecan=off
in the media description part. This attribute signals the remote device of the new media transmission. If the
command option default is selected, the system behavior is the same as before.
SmartWare also supports the Cisco NSE standard which uses RFC2833 events for modem transmission over a
VoIP (SIP or H.323) network. Upon detecting a modem transmission, the called peer issues NSE Event 192.
NSE Event 192 indicates a Voice Band Data stream that forces the calling peer to deactivate Voice Activity
Detection and to reconfigure the Dejitter Buffer for data reception. Afterwards it issues the NSE Event 193 to
trigger the calling peer to switch off Echo-Cancellation.
Mode: profile voip
2
[name] (pf-voip)[pf-name]# fax
transmission 2 bypass
g711alaw64k
Define G.711 A-Law as the second fax transmis-
sion method to try, if T.38 is not supported by the
remote gateway.
Step Command Purpose
1 node(pf-voip)[name]#modem trans-
mission bypass g711alaw64k
Adds modem transmission with codec G.711 to
the list of fax transmission modes.Alternative
codecs available are:
• G.711uLaw
• G.726 32kbps
• G.726 24kbps.
Step Command Purpose
1
[ name] (pf-voip)[name]#modem
bypass- method {default | v150-
vbd | nse}
Specifies the modem bypass signaling method.
Default: default
Step Command Purpose