Configuring Modem Transmission; Modem Bypass Method; Examples; Home Office In An Enterprise Network - Patton electronics SmartWare R.3.20 Software Configuration Manual

SmartWare Software Configuration Guide
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
Step
node (pf-voip)[ name ]#modem trans-
1
mission bypass g711alaw64k

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
Step
1
[ name ] (pf-voip)[name]#modem
bypass- method {default | v150-
vbd | nse}

Examples

Different applications require different VoIP profiles. This section includes a variety of applications and show
how the VoIP profile for these applications would be configured.
Home office in an enterprise network
Figure 84 is an example of a home office in an enterprise network. The connection bandwidth is 128 kbps and
is of very low quality, so the low bit-rate G.723_6k3 codec is used. Likewise, silence suppression is enabled.
Examples
Command
Command
40 • VoIP profile configuration
Purpose
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.
•
Purpose
Specifies the modem bypass signaling method.
Default: default
522