Agilent Technologies N2620A - Manual (Page 112)

94 N2620A User’s Guide
3 Voice Testing with the FrameScope Pro
FrameScope Pro as the Caller
If the FrameScope Pro is configured as the caller, it uses the audio
codec according to the user-defined media negotiation on the SIP
screen of the SIP test, or the Phone Settings screen of the Megaco
test. These screens can be reached by pressing Settings on the main
screen of either test.
To configure the FrameScope Pro as the caller, clear Auto Answer
Incoming Call
.
If Headset Call is not selected, a WAV file with a length of 40 s will be
used. The VoIP consortium certifies this file.
If you choose a codec from the G.721 or G.726 family, the G.726
Stream Properties
panel will be available for configuration.
• Select A-Law or µ-Law
• Select Little or Big for the Endian panel
Press OK to return to the main screen of either test, where additional
settings can be made and where the test can be started.
FrameScope Pro as the Callee
The FrameScope Pro supports all available codecs when it is
configured for the callee mode. The audio codec used is defined
during the media negotiation between the caller and callee.
To configure the FrameScope Pro as the callee, select Auto Answer
Incoming Call
on the SIP screen of the SIP test or the Phone Settings
screen of the Megaco test. These screens can be accessed by pressing
Settings
on the main screen of the test.
The suitable codec is selected according to the order of preferences
of supported audio codecs in the incoming SIP INVITE message. For
example, if the caller provides the following sequence of supported
codecs; G.723.1
→ G.729 → G.711 A-law → G.711 μ-law, then the
FrameScope Pro as the callee, will select codec G.723.1 in the SIP
RESPONSE
returned message to the caller.
If no common codec is found between the caller and callee based on
the media information in the incoming SIP INVITE message, the
FrameScope Pro will return message 488 Media Not Supported to
the caller side.
In callee mode, choose the preferred stream properties for the G.721
or G.726 codec family in the G.726 Stream Properties. The setting is
only used if the caller and callee negotiate a codec from the G.721 or
G.726 family, otherwise it is disregarded.