Achieving Optimum Voice Quality

Voice Quality – Recommended best practices to ensure you get the best VoIP experience

Internet Speed

The faster your Internet upload and download speed, the better the quality of VoIP services, that’s the simple undeniable fact.  Faster Internet speeds also allow you to talk and surf simultaneously, whereas with a slower internet connection talking and surfing simultaneously will affect both voice quality and Internet download times.  However, speeds from 384Kbps can be used if you use your Internet optimally and do not talk and surf simultaneously.  For example, a 384Kbps ADSL line has a download speed of 384Kbps, but the upload speed is only 128Kbps, sufficient for using VoIP, but not recommended if you plan to talk and surf at the same time.

The required Internet speeds can be achieved on a variety of broadband Internet connections, like ADSL, 3G, and Wi-Max.  ADSL is probably the most stable, as the upload and download speeds are rather constant.  3G users may experience variable speeds depending on their distance from the cell phone tower, and the number of different users that are connected to a particular 3G connection simultaneously.  Wi-Fi users may also experience variable speeds, depending on the size of the Wi-Fi connection at the specific hotspot, and the number of people that connected at the particular hotspot simultaneously.

Which codecs does VOIP Services support?

In simple terms, VoIP works in the following way; a special piece of software a chunk of sound, and converts it into a data packet.  This data packet is sent across the Internet, and when it reaches its destination, the codec will convert the data packet into the original sound for the recipient to hear.  How the codec actually converts sound into data, and the size of the resultant data packet that it creates, differs from codec to codec, but it has a huge impact on the sound quality you experience.  Small data packets that travel across fast Internet speeds offer superior sound quality and less lag time than larger packets that have to travel on slow internet connections.

The table below shows a sample of the codecs in use today, and the bandwidth required to use each of them optimally.

Bandwidth Required (upload and download speeds) Codec Name Device Availablity
31.2 Kbps  [0.31MB per Minute] G. 729a Available on most Commercial Softphones, Desktop VOIP Phones and Software PABX Systems
87.2 Kbps  [0.87MB per minute] G. 711U/A Available in most free softphones