OT - Some VoIP Clarifications, if you please...
Keith, your point is well taken about the adequacy of today's voice to do what needs to be done to suit your needs for now. When VoIP is properly introduced over CM and DSLs in the future, you wont know the difference between these and traditional POTS as you have become accustomed to it, save, maybe, for some delay/latency artifacts, at times.
Also, while ADSL has the ability to support both analog voice and digital data for Internet access, etc., there is nothing precluding the ADSL "data" link from supporting VoIP, as well. I suspect that we will see quite a bit of VoIP over those DSL lines which have return (uplink) capabilities which are 64 kb/s and above. The normal VoIP packet is rated at only from 6 kb/s to 8 kb/s, depending on which algorithm is used. Add another 6 kb/s for overhead and guard-margining, to remain conservative.
Jing, if I might ask, which VoIP products do you know of at this time that use MPEG, besides some modes of ISDN, perhaps, to convey IP supported forms of telephony?
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Voice recognition does indeed work today with normal POTS/PSTN services, only it takes an additional encoding step in the DSP chip set when it is received, but that is transparent to the user. Actually, in many cases additional steps will be needed with true VoIP as well, since the received VoIP will need to be flash-converted by the DSP to a standard that it uses, since there are many different emerging algorithms being accepted by the VoIP model. Even Cellular and PCS wireless coding will interface here.
This is a poor example, but most modern PSTN telephone exchanges are currently equipped with Voice Recognition technology to allow you to dial the number by saying the word "one," or some such thing.
Re: Voice Reognition in POTS systems: Some trading desks have been using this technology in the analog native form as well, to input screen information in trading systems. And there are a growing number of call centers which provide customized 800 and follow me services to subscribers which take their instructions in the way of the spoken word over analog lines, as opposed to touch tones or DTMF tones, and the list doesn't stop there.
By the way, VoIP packets are like little cockroaches, and they will "get through" on DSL and CM equally well. VoIP does not employ MPEG at this time, and probably wont except for an enhanced form of audio during conferences, and for the delivery of program [entertainment] audio services such as FM stereo over the 'net.
Of course, there may be proprietary adaptations of MPEG in certain VoIP products, but these are by no means the standard approaches being formalized at the IETF and the ITU levels for packet voice telephony. Instead, the latter employ G.723 and G.729 algorithms which are different from MPEG. FWIW.
Regards, Frank Coluccio |
