DSP Voice Processing

[BBateman]

Has anyone read a good article on the role of DSP processors in VOIP and analog streams? Specifically, I am interested in the technical aspect of why an analog or conference line need so much more processing power then an IP stream. A 5 to 1 ratio for conference or analog ports to IP is pretty significant amount of processing power. I do know that DSP processors play the role of echo cancellation, pulse code modulation, compression, codec conversion, and tone detection/generation in a phone system application but not clear why one data type needs that much more horsepower. Why does a conference call need five ports per line? Could the conference port allocation be dynamic rather than static (preassigning conference ports)? With more powerful DSP chips being released all the time, why didn't Shoretel's new voice switches have a two to one ratio. Instead of a 60/12, it would be a 60/30? What manufacture does Shoretel use for cpu and dsp's?
Inquiring minds want to know!!!

[Jlorenz]

Originally Posted by BBateman

Has anyone read a good article on the role of DSP processors in VOIP and analog streams? Specifically, I am interested in the technical aspect of why an analog or conference line need so much more processing power then an IP stream. A 5 to 1 ratio for conference or analog ports to IP is pretty significant amount of processing power. I do know that DSP processors play the role of echo cancellation, pulse code modulation, compression, codec conversion, and tone detection/generation in a phone system application but not clear why one data type needs that much more horsepower. Why does a conference call need five ports per line? Could the conference port allocation be dynamic rather than static (preassigning conference ports)? With more powerful DSP chips being released all the time, why didn't Shoretel's new voice switches have a two to one ratio. Instead of a 60/12, it would be a 60/30? What manufacture does Shoretel use for cpu and dsp's?
Inquiring minds want to know!!!

As far as what manufacture Shoretel uses, I would suggest you contact your ShoreTel SE or Partner to discuss that. What I can say is the design of the ST SG is designed for optimum performance, it is what it is.

If you are speaking about the Make Me Conference feature, then let me explain a tad bit on that.

The IP phone will only handle up to 3 in a single conference, that is 1 (The Originator) plus 2 (Conference's) The fourth added conference will move directly to the SG (All 4)

The SG must have at minimum 4 and maximum 6 to give a 6 Party conference, That is 1 (The Originator) plus 5 (Conferences)

You can dedicate a single SG (IE SG120) for Make me conferencing giving you 24 very expensive Conference ports. But each single user is only able to conference up to 6 "Including Self" 1 plus 5

You have to remember that the SG has far more responsibility in the system then just processing Voice and call control. It as to maintain its identity / integrity in the system as well as keep track of Hunt Groups, Dial Plans and so forth. The latest SG's offered SG50, SG90, SG220 are a step into better technology and performance. Like all manufactures, they design the system to a best fit, with cost, performance and get to market quickly mentality.

Now, conference phones, such as Polycom IP4000 or the IP8000 are all designed internally with Echo cancellation, speaker mic ambient noise ratio. Each phone has its own specifications to what room capacity it is designed to be fitting. A ShoreTel IP phone aka 56x, 26x and so on, are not designed to be a conference room phone, they are business phones