March 11, 2005
Skype, SkypeOut, Codecs and ATAs
Andy writes that the million or so SkypeOut users get “less than a great experience with sound despite GIPS being in place.” It was known long time back that SkypeOut uses G.729A and that its quality will not be as good as Skype calls because the latter uses a wideband codec. Looks like the interconnect providers still do not see the need to upgrade their gateways to support the wideband codec.
While we are on the topic of codecs, one of the issues with ATA based deployments is that it is not feasible to add wideband codec to the ATA, since the standard telephones sample only at the baseband. I hope that the new breed of cordless phone based IP phones pay attention to this and build their handsets so that they can operate at the wideband frequencies.
Posted by aswath at March 11, 2005 07:42 PM
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Excellent comment. My thoughts exactly. The wideband codec is so much richer and really shows-off the sound advantage of IP as seen in Skype to Skype codecs from Global IP Sound.
But please, don't ever think that everyone wants to migrate to cordless. Personally, I still hate cordless phones for many reasons (batteries that run out during calls and the possible unknown effects of having a microwave-frequency transmitter that close to my brain are two) and while I would love to see someone come out with a wired telephone with better frequency response (and ATA's to match) there is no way I want to be limited to using a cordless phone in order to use VoIP.
I also think that people don't understand that in residential settings, people are used to the idea of having phones in several rooms and when a call comes in for another family member, you just holler to them to pick up the closest phone. If necessary you can even do an ad hoc three (or more) way call by having family members pick up multiple extensions, not an uncommon thing when a far-flung family member calls and everyone wants to hear what they are saying.
So, please, do not assume that wireless VoIP phones will be the last word in telephones - there will always be some of us who want to use a wired phone and for many people in homes with wired phones, that may be the rule rather than the exception (and I think that would be even more true if some of the studies in other countries showing the harmful effects of some wireless phone transmitters on the brain were widely published in the United States).
I was not advocating only cordless handsets based IP phones alone. I mentioned them because I have seen only such phones. The main point is that we need mic/speaker operating at wideband frequencies. For me it is immaterial whether they have wired or wireless connection. Your suggestion about wired "handset" connected to "ATA" works for me. But I do not want to reuse the term ATA in that case; the first A (Analog) suggests to me that the standard phone is connected.
I agree with your first statements, but as for the "analog", I've never seen digital VoIP phones that will allow the sort of ad-hoc conferencing that is a "feature" of analog telephones, in other words, the ability to listen in on an extension phone. That's not to say it couldn't be done in digital, but I'm afraid the designers of digital wired phones would try to sell the inability to do this as a privacy feature (which it is, but it's not a feature everyone would want, particularly not residential users). I personally would not care if the signal between the adapter and the phones was analog or digital, but I would mind a lot if the new crop of phones takes away capabilities that I now have with my analog phones (or make me push buttons to do what now happens automatically).
The point of this entry is not about "wired" vs. "wireless" or "analog" vs. "digital". It is simply that with VoIP we could and (I am suggesting that we should) have wider frequency response in the mic/speaker. I am concluding that based what you have said that you are suggesting that we should not lose other aspects of standard telephones - natural bridging, quality of wired connection etc.
By the way, even digital cordless phones permit natural bridging among multiple handsets, by mixing them at the base station. Granted, in the wired, analog world the wire itself is the bridging point.
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