Hi,
I am running a small export business which requires me to hold mainly
audio conferences with 3 or more of my clients from time to time.
Rather than purchase any audio conferencing software I would like to
make use of Yahoo Messenger if it can serve my purpose. I came to know
through Yahoo Help desk that Yahoo messenger can support and audio
conference with webcam for upto 30 people at a time. But that the
number of Webcam and Voice IM windows I can have open is limited only
by my computer's memory and your internet connections bandwidth. The
question is how much bandwidth and how much memory is required for
conferencing with say 25 people. How much bandwidth is required for a
pure conference and how much if a webcam is also used? Is there any
authoritative guide or reference page on the net which will furnish
this information?

Let's say it takes (conservatively, perhaps) 16Kbps to serve
voice-only per recipient. This is perhaps a bit garbled, but the point
is that you can do audio conferencing to a person who has a 28.8kbps
connection. It's compressed voice, to be sure, but the content is
reasonably intelligible. That means that 25 people would require
25x16=400Kbps bandwidth of voice only. This is *usually* more than
you'll get with your standard DSL, ISDN, or Cable up-wise bandwidth
(about 128-256Kbps, unless you have SDSL which is the same up and
down, starting about 640Kbps.) However, using a service like Yahoo!
can help because it can have the ability to agregate the bandwidth for
you. That means that it can possibly be a bounce-point for your
message. (You only have to provide bandwidth for your connection to
Yahoo! and Yahoo! rebroadcasts on its bandwidth to the recipients).
However, if that were the case, I don't really know why your bandwidth
would be an issue.

But, let's add some overhead in the form of a webcam. Your webcam
image may be 320x240 or 160x120, so let's take the smaller. A 160x120
image may run (with lossy compression) about 2-3KiloBytes (16-24
kilobits) per image. Assuming one image per second, this effectively
doubles your bandwidth requirements per recipient. Faster video (15
frames per second, nearly real time), ... well, you get the idea.

That doesn't mean it doesn't and can't happen. I've VC'd with up to 8
people and 3 cameras via Yahoo!, and though it wasn't important, it
did work. However, if it is important to make a better impression, may
I suggest a service like www.webex.com?

As for memory, well, more is certainly better. If you have 256MB
(about the minimum sold nowadays in new PCs) you're on the right
track. However, 512MB might be a good happy medium. Still, if you use
a service that rebroadcasts for you, your bandwidth and memory
requirements are probably not so much the issue.

This is a free comment.

Thanks crythias-ga, you have provided lots of food for thought and met
all my requirements through your free comment. I really appreciate it.