Re: ISDN/CU-seeme/QuickCam wisdom request

Ashesh C. Shah (
Thu, 19 Jan 1995 13:17:35 -0500

>At 06:31 1/18/95, Jud Elliott wrote:
>>Any CU'ers using ISDN and/or ISDN with the QuickCam are asked to report
>>your results...

and Michael Sattler wrote:
>A single channel (56 or 64 kbps) is much better than 14.4 or 28.8 kbps.
>Two channels (112 or 128 kbps) is better again. With dedicated compression
>hardware (as might exist at multiple sites on a school or office campus)
>you can jack the thruput up as much as 4x (but I'm not sure how well a
>CU-SeeMe video stream will compress.

We currently have a two channel ISDN connection with dedicated compression
hardware (essentially a router with some brains, list $1300) and we are
getting upwards of 14 fps with the PC version. I am sorry I don't have the
kbs figures memorized, and I am on the road. I couldn't tell you what the
compression ratio is, but an ISDN connection is well worth it. However,
remember it is important to know the bandwidth of your internet provider's
connection. When you are up at a two channel ISDN connection the provider's
bandwidth could become the resticting factor if they have a number of ISDNs
and SLIPS hooked up to a fractional T1 or less. Moreover the fps will
depend on what the sender's bandwidth.

Hope that helps.


||||||||| |||||| ||||||||| Ashesh C. Shah (aka) Alex
||| ||| ||| Sales Director
||| ||| ||||||| 675 Mass. Ave. Cambridge, MA 02139 USA
||| ||| ||| V. +1-617-441-5544 f. +1-617-267-7515
||||||||| |||||| ||||||||| If at first you don't succeed...reboot