Ask Mr. Andrews: What is HD Voice?
Q: Dear Mr. Andrews, I have heard some terms lately including “HD Voice”, “Wideband VoIP” and “Wideband Audio.” Do you know what’s behind this and which manufacturers support it?
A: These are industry marketing terms which typically refer to the use of higher quality voice codecs, such as G.722, to deliver voice quality and richness on a VoIP call that surpasses the quality that is possible on a traditional PSTN call. A PSTN “toll quality” call or mobile phone call is limited by the bandwidth (300-3,300Hz) utilized in the PSTN. An IP based call can take advantage of technologies that may require additional bandwidth but can deliver superior call quality.
G.722, the ITU’s wideband speech codec captures 7,000Hz (7kHz) of bandwidth, more than twice the amount of speech data in a traditional TDN/PSTN call, enabling new levels of voice clarity. This increased call quality facilitates both parties in a conversation being able to better distinguish between vowels, consonants and other nuances of speech, reducing listener fatigue and improving concentration.
Polycom has been banging the drum loudly for “HD Voice”, and they have built in G.722 codec support into most of their newer SoundPoint IP Series phones, including the IP550, 560 and 650 and their IP6000/7000 Series conference phones.
Cisco supports G.722 wideband codec on their CP-7942G, CP-7962G, CP-7945G, CP-7965G and CP-7975G Unified IP Phone models. Additionally, the CP-7906G, CP-7911G, CP-7931G, CP-7941G-GE, CP-7961G, CP-7961G-GE, CP-7970G and CP-7971G-GE models can be upgraded to support G.722 with an option wideband handset or headset.
Snom recently released an accessory handset called KlarVoice that is compatible with all their IP phone models (300, 320, 360, 370) and adds G.722 wideband capabilities to their existing phone models. In addition, their new 820 model offers native support for wideband audio.
Grandstream and Aastra also offer support for G.722 in many of their products.