Don Johnson (
Mon, 24 Apr 1995 23:38:12 -0400

ISDN stands for Integrated Services Digital Network or to the phone company:
"I Still Don't Know". I set up a Picture Tel Video Conferencing system
between Arizona (U. S. West) and Orlando (Southern Bell) and AT&T as the
long distance service provider. It was something like 2 "D" channels and one
"C". The latter channel used for signaling and the 2 D (128K) channels for
audio, video and data. This kind of bandwidth is neccessary to obtain about
15 frames per second (1/2 the FPS of a vcr being 30 fps). I recall the
monthly cost at about $80.00
per month per channel, significantly higher than what is stated below. In
addition their are long distance charges for each line paid to the L D carrier.
and set-up charges for the lines which were substantially over $100.00. For
conventional video conferencing systems, multi-point is another expense. A
multi-point bridge is so costly that most people use a "service" and pay a
fee to the service provider. In our case, we used a Northern Telecom NT-1
interface to the network at each end. A modem is not used since it is a
direct digital connection.

I have recently found a WEB site dedicated to ISDN products and services. If
anyone is interested EMail me direct. If lot's of interest I will post it to
the list.

Thanks for the time,

Don Johnson (Orlando, Fl USA)

Evil deeds are but shadows walking across a great Light.

>[Text item: Re: ISDN]
>ISDN is a digital telephone line that allows you to communicate at 64kbs.
>Basic rate service is 2 channels (64kbs each, but you can use only one).
>Pacific Bell offers this service in most of California for $25/month and
>the per minute rates are very close to standard telephone rates per
>channel. Installation is about $35, plus they don't charge you the $110
>setup fee if you keep the line for 2 years. Call Pac Bell at
>Note: you will also have to buy an ISDN "modem" for your computer (ex for
>PC- IBM Waverunner :$500) plus an Network Terminator 1 (NT1) adapter
>(Motorola, IBM: $150-350).
>Also, you will need to know the configuration you want for your ISDN (there
>are many options) This will depend on the ISDN card you use. I've just
>ordered mine recently, so I'll know more in a few weeks.
>What is an ISDN Connection?? How do you get one and how expensive will it
>I've been watching my CU-SeeMe reflectors with great hope and interest, but
>I've been terribly dissapointed with the slow frame rate ( .5-6.5 fps )
>except Barre @home who always seems to be cranking out 10 fps.
>How can I improve this performance?
>I'm running...
>Mac Performa 600 (680030 33 mhz)
>Supra 14.4 modem
>Elliott Francis
>Black Entertainment Television
>Burbank, California
>DisplaySubject: Re: ISDN