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Appendix A: Troubleshooting ADTRAN IP SoftPhone User Manual
48 Copyright © 2006 ADTRAN, Inc. 61950859L1-1A
There are several factors that may affect sound quality when using the ADTRAN IP SoftPhone. These
include the quality of the network connection, quality of the network device, and headset model. Some of
the common problems experienced are given below, along with useful tips on how to minimize their effect.
Audio contains pops at loud points in voice
Popping sounds are a symptom of over-modulation. Ask the other party to decrease their microphone
slider and/or adjust the microphone gain.
Audio contains bothersome background noise
Significant background noise can be due to the level of the silence threshold. Have the other party adjust
their silence threshold, which they can do by running the Tuning Wizard.
Audio sounds choppy in a conference
Poor conference audio may be caused by upload bandwidth limitations. For example, some sites have
1 Mbps download bandwidth, but only 128 kbps upload bandwidth. Under such conditions, try multiple
hosts for the conference, or have all participants disconnect and switch to a lesser bandwidth audio
compression CODEC such as G.729.
Poor sound
Poor or scratchy sound is a symptom of a problem with network connections or a faulty network card. The
following issues could contribute to poor sound quality.
• There may be packet loss on the IP network. Check the network performance, latency, and
throughput. A 200 millisecond round trip latency as determined from a ping should deliver good
audio quality.
• Older network devices may have performance problems. Make sure to use the latest driver.
There is an echo
The following tips may be useful for reducing echo heard during the conversation.
• Try using a headset plugged into the sound card. Another suggestion is to use a USB-enabled
headset, which bypasses system sounds by acting as its own sound device.
• If using a boom type headset, note that some boom headsets can create feedback between the boom
microphone and the headset earpiece.
• The microphone volume may not be muted in the playback section of Windows audio controls.
When configuring sound, check the Windows volume control setting.
• Echo will occur if the microphone can pick up sounds coming from the speakers used for the
softphone call (when not using an integrated headset).
• The microphone level might be too high or the amplifier might be turned on in the generic Windows
audio controls.
One-way Audio
If a firewall restricts incoming connections, the result can be one-way audio. Configure the ADTRAN IP
SoftPhone to use the service provider’s Outbound Proxy (if available), as explained under Firewall and
NAT Issues on page 46.