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Sending VOIPSCHOOL.ORG Back To School About HDVoice

While not as negative in tone as the first post it continues in the offering of marginal quality information.

“As HD voice continues to become more prevalent, the industry will push for a single wideband codec.”

There may be a desire for a single wideband codec (Boy is there!), but it will likely never happen. Just as the PSTN lives on with a handful of more common codecs (G.711, G.723, G.729, G.726, GSM, AMR)  wideband voice will likely get down to a small subset set of what is currently being considered. My guess is that we’re going to live with perhaps 3 or 4 in the end.

Some companies, like Audio Codes, will benefit from the use of multiple codecs since it creates demand for media gateways capable of of wideband transcoding. Even their new line of HDVoip desk phones only supports G.722 at present.

“However until then, it’s important to do research on the type of codecs that are integrated into your HD phones.”

That’s difficult. There simply aren’t very many wideband codecs deployed in desk phones at the present time. G.722 dominates and can be found in phones from every major vendor of IP phones.

The exception being cell phones. There are extremely few cell phones at present that support wideband, but where they do AMR-WB (aka G.722.2) and EVRC are the most common codecs.

The apparent gulf between the mobile and fixed line world is why I expect that we’ll never get below 3-4 codecs. The GSM folks will settle on one and the CDMA proponents will pick another. Then the wireline industry will pick something more ideal for their needs. That’ll be 3-4 codecs at the end of the day.

Where there are a myriad codecs offered is in the realm of soft phones. But my sense was that you aren’t really talking about that. Are you?

“There is more to HD voice than the codec.”

Haleluia! That’s very, very true!

“While HD compatible phones exist it is probably a better idea to go with HD capable phones. “

I don’t see a solid reason for the distinction between “HD compatible” and “HD capable.” I see no marketing for compatible vs capable in the various manufacturers literature.

Snom supports G.722 in all of their 300 series phones, but requires an upgraded “KlarVoice” handset to truly deliver the goods. Maybe that’s what you mean, but they’re the only one. There’s no trend behind that.

I don’t think any manufacturer is trying to trick people. It’s simply a matter of getting what you pay for. If you buy a very cheap phone don’t be too surprised if it looks, feels & sounds like a cheap phone.

“Second, it’s important that your service provider can properly transmit HD voice. Any call made outside the company that has to jump on a PSTN won’t be HD quality, but by choosing the right provider calls made in office or between company branches can be guaranteed HD. The trick is to make sure that your provider offers end-to-end SIP. SIP, or session initiation protocol, checks each of the end points to see what codecs they have in common and then transmits the call in the highest possible quality. In this case, the use of different HD phones or soft phones doesn’t have too much of an effect on HD call quality.”

There’s something about this that just isn’t clear. Yes, SIP is important. An end-to-end IP call path is critical to wideband calling. But you don’t even mention the concept of SIP URIs, which are a key aspect of making wideband calls. Nor do you mention hosted IP-PBX solutions, which are a great low-cost way to deploy HDVoice.

BTW, the term HD is getting thrown about in telecom with reckless abandon. What we’re talking about here is “Wideband IP Telephony.” HDVoice is a registered trademark of Polycom.

I truly do appreciate blog sites that try to introduce technical matters to the uninitiated. It’s a sometimes daunting task, and never easy. One of the things that motivated me to start writing this blog was time spent answering questions in public forums like VoIP Tech Chat on DSL Reports. I still do that as a matter of routine. See here, here, here and here for examples.

What causes me such consternation is the fact that VOIP School is a nicely done site. In fact, it’s listed as part of AllTop. That would seem to impart some serious credibility. Perhaps this topic was just a stretch for the author.

Anyone even vaguely interested in wideband VoIP should come on by the VoIP Users Conference one Friday and get some first hand experience using the techology. They’re a tremendous group of very experienced VoIP aficionados who are happy to help interest folks starting out with wideband voice.

And most of them are a lot less irritable than I might appear to be.

This Post Has 8 Comments
  1. Michael,

    It’s worth mentioning that some providers will do HD within their network, so that if you have an account (even a free one) with or, calls between your extensions will be made in g722. Obviously you need a phone, hard or soft, that will do g722. Today, even the high end of technology, Polycom, has phones that are very cost-effective, and as you mentioned, Siemens has one as well.

    I would also argue that even if you are not connected in g722, on a conference where the speaker is using g722 and you have a high end phone, the quality will still be noticeably better.

  2. It appears that the admin over at decided to remove my comment without going to the trouble of a response. Nor did they remedy any of the errors, omissions or vagaries of either of the posts.

    1. This is what I had originally though as well. In looking at the web site and the downloadable tech sheets I found that only G.722 was listed in the tech specs, although the marketing copy mentioned G.722.2 (AMR-wB) making the situation a little unclear.

  3. I disagree with their reply to you and in no way did I see you backpedal or anything of that sort. I also agree with your declaration that there are patently false statements in their post and that even the placement of those facts underneath a subject line of “what’s the catch” further emphasizes the erroneous statements. Not sure what the motive behind their response is, but the actions of taking down criticism speaks volume. And it speaks it so clearly… it’s as clear as an HD Voice call.

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