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Interruption and bad sound quality
VoIP requires at least 100Kbit/s for both up and downstream. Therefore, if possible please avoid downloading large amounts of data (e.g. audio/video streaming, opening emails with large attatchments) while making or recieving calls. This uses a significant amount of bandwidth and could considerably degrade the sound quality depending on your connection type.

Possible symptoms may include speech clipping (garbled sound) or even calls dropping out altogether.

As many broadband connections are typically asymmetric (download and upload speeds are different), with slower speeds for upload, the sound quality you hear (download) can be much better than the quality heard by the called party (upload).

This could be caused by using a high bandwidth codec.

Possibe solution: Change to a lower bandwidth codec (refer to your phone manual). G729 is recommended, if your phone does not support G729, try another codec. A list of codecs supported by sipgate follows here:

G.729

G.711

iLBC

GSM

G726

Please feel free to try each codec in turn and see which one works best for your connection.

Also consider the quality of your broadband connection. If you find that speech quality issues are at similar times of the day this is commonly caused by heavy internet traffic as a result of contention ratio. (Dedicated business services are generally on a 20/1 ratio and residential 50/1). Naturally, peak times such as evenings could have an impact on the performance of your service.

Possible solution: Talk to your broadband service provider regarding a possible upgrade.

Strong interference on the line

If your call is accompanied by strong interference, please check your microphone settings (you can find it under Start -> Control Panel -> Sounds and Audio Devices). Please be advised this example refers to Windows Xp. Your operating system may differ.

Echo during the call

If your call is accompanied by a continual echo, you can try the following to resolve this:

A possible solution is the use of a USB headset.

For softphone setups (X-Lite) "the reverse UDP mapping rule" can cause an error because the sound is only transferred in one direction. In this case, please implement the following adjustments in the settings:

• Click the Menu (Symbol is on the right next to Clear) - Advanced Settings - RTP Settings - Obey Reverse UDP Mapping: No (Please be advised this tip refers to X-Lite).
  

There are many different variables regarding firewalls and routers which make it almost impossible to test and to publish all potential problems. Therefore, please understand that sipgate cannot provide support in all cases.

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