2009-09-02 - Wideband Telephony - A reality in SA yet
What is Wideband Telephony
Wideband Telephony, also known as industry trademarked terms HD Voice (Polycom), HD VoIP (AudioCodes) and HDSP (Gigaset) , refers to the use of higher quality voice codecs to deliver audio quality far superior to any cellular, PSTN or “traditional” VoIP call. A voice codec (if you’re unfamiliar) is what converts an analog voice signal to a digitally encoded version.
Just how superior is Wideband Telephony to traditional calling? Very. G.722, the most popular and widely used Wideband telephony codec, captures the sound spectrum up to 7,000Hz (7 kHz). This means nothing until you learn that the average cellular or PSTN call only captures the sound spectrum between 300 – 3,300Hz (3.3 kHz). With twice the sound spectrum captured you get exposed to a whole new range of sound that increases the clarity and crispness of the calling experience. Hence all the excitement.
The reality in South Africa
Before you get too excited at the prospects there are a few implications that make Wideband Telephony a challenge in the SA context. Firstly in order to experience a true Wideband call both participants must be using a Wideband codec and Wideband phones. Most people you are likely to call these days aren’t using Wideband Telephony. However as VoIP continues to take market share from land lines and cellular networks move to 4G, Wideband Telephony’s presence will increase.
The other major challenge in SA is obviously bandwidth constraints. The wideband codec G722 uses condsiderably more bandwidth than other codecs. At the moment all local VoIP providers (Vox, ECN, iBurst, MWeb, IS etc) restrict the codec to G.729 because it is the best compromise between low bandwidth and decent quality. There are various bandwidth calculators which help to explain this, nice simple one here…
What do you need for Wideband Telephony
So it may not quite be a reality in SA yet but what would you need when it is available? Firstly, Wideband Telephony starts at the voice carrier, hopefully we will see some SA providers supporting wideband in the not too distant future. Next you’ll need to ensure that your IP based phone system or VoIP gateway also supports the G.722 codec. As you can tell, capability and support are essential to ensuring a quality Wideband calling experience.
With a Wideband friendly service provider and system in place, the last stop is the desktop. Given the growing support for and adoption of Wideband Telephony, a number of VoIP equipment manufacturers have released desktop IP phones that support Wideband codecs. Led by Polycom and their HD voice line-up, you can find IP phones that support Wideband codecs from many popular manufacturers such as Aastra, AudioCodes and Snom. Snom has been especially active in Wideband with the release of the Snom 820 and Snom 870. Although there are a number of choices available today, expect to pay a premium for them. Over time prices will fall, but for now you will pay a little extra.
Conclusion
Although not an option yet in South Africa, Wideband Telephony holds good promise when bandwidth service and costs improve and HD voice will hopefully help turn around the general negative sentiment in regards to VoIP user experience and call quality issues in South Africa.
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