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Voice-over-IP FAQ

Codec Selection

  • Which Codec is best to select ?

    The Vigor VOIP routers support various different Codecs; these are voice coding methods. The current setting (that used for placing outgoing calls) is set from the VOIP/Codec menu. The default setting is G.729A/B which offers a good balance of voice quality and modest bandwidth usage but with a broadband connection, you may wish to select the higher quality G.711 codec. Do remember that your broadband connection's upstream speed may only be 256Kb/s in total (even if your downstream speed is 4Mb/s!) so for an activity like VoIP, your upstream speed is important.

    You can experiment to see which protocol suits you best. You can also select the packet size; this is set in ms (milliseconds); for example if it is set to 20ms, that specifies that each packet will contain 20ms of voice data. If can increase the value the packet overhead is smaller, but latency (voice delay) will increase, and vice versa. Again, you can experiment to find your preferred setting.

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