Choppy voice on a VoIP connection is usually an issue with insufficient or unavailable bandwidth. A typical two-way conversation takes about 90kbps on both the upload and download on a G711 codec. (There are other, more compressed codecs that can reduce the required bandwidth, G729 being a popular one.) In some cases you could have enough bandwidth from your ISP but a computer application is grabbing the available bandwidth, essentially taking it away from the VoIP transmission. Usually bandwidth issues result in brief dead spots in the conversation, sometimes described as a stutter or a staccato sound.
- Try turning off all your computers to see if the issue still occurs.
- Test your bandwidth, both upload and download.
- Check for file sharing software, these programs usually run in the background and use your bandwidth to upload files.
- Check your computer for malware and Spyware.
- If your router has QoS, then enable it for your VoIP connection.
Your bandwidth should not be continually less than 80% of your ISP's subscribed level of service. If it is, then you should have your ISP's technical support look at your connection.
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Typical bandwidth* usage for different codecs.
- G711 - 87.2kbps -This is the best quality codec.
- G729 - 31.2kbps -A compressed good quality codec.
- G723.1 - 21.9kbps -The codec best for satellite, (more compressed).
- G726 - 55.2kbps
- G728 - 31.5kbps
*These figures are the nominal Ethernet bandwidth one-way and are only for the voice traffic on a single call. To calculate how much bandwidth would be required you will also want to consider internet use by computers and other devices. (Also, remember a three way call (two parties called), will take twice the nominal bandwidth.)