Nortel 2001 Installation And Operation Manual page 165

Audio Quality
This slider allows the user to choose the balance between low delay or higher
quality audio. The slider adjusts the number of buffers between the PC's
audio device and the IP Softphone 2050 application. Less delay is achieved
by reducing the number of buffers; however, this increases chances the
buffers can run out, resulting in poorer audio quality. The Less Delay setting
requires the PC's CPU to give attention to the application more frequently
and should be chosen on newer PCs with fast CPUs.
Choosing Higher Quality increases the number of buffers, making buffer
under or overruns less likely, but increasing the end-to-end delay. If choppy
or broken speech is heard, move the slider toward Higher Quality to see if
that eliminates the problem.
When a modem is used to connect to the network
To connect to the network using a modem, the user must select the I use a
modem to connect to the network check box (see Figure 22 on
The TPS queries the IP Softphone 2050 during the registration process for its
codec capabilities. The IP Softphone 2050 responds with the low bandwidth
codecs, G.729A and G.723.
The check box combined with the TPS query of the codec list, enables the
user to force the IP Softphone 2050 to use the low bandwidth codecs without
the craftsperson needing to configure two TNs in different zones.
Changing the check box option requires the user to close and reopen the IP
Softphone 2050 client on the desktop to re-register the IP Softphone 2050
with the TPS for the change to take effect.
When supporting IP Softphone 2050 users on modems, the customer needs to
configure G.729A/B and/or G.723 on their node.
Note: If only G.711 is configured in Element Manager/Optivity
Telephony Manager (EM/OTM) for the system, then calls with the IP
Softphone 2050 are blocked. As long as G.729A/B and/or G.723 are
selected in EM/OTM as a codec option, calls won't be blocked. When
there is a codec mismatch, the caller hears the reorder (fast busy) tone.
Nortel Networks IP Softphone 2050
IP Phones Description, Installation, and Operation
Page 165 of 302
page 164).