25 Apr 95 10:02

[Text item: Re: ISDN]
The availability and cost of ISDN still varies widely depending upon your
local telephone companies investment in the digital telephone switches
needed. Pacific Bell is one of the best able to provide ISDN and it is
also one of the cheapest (they are aggressively pushing it). I have
heard that southwestern bell is one of the worst.

I am familiar with the 2B + D channel Basic Rate Interface (BRI)
configuration. Each B channel carries 64kB/sec and counts as one
telephone call for figuring the per minute rate (ie - a 2 B channel call
costs 2x a standard call). The D-channel is smaller (16 kbs?) and is
more for signaling purposes during the call rather than data.

My experience is with setting up Vivo 320 desktop video conferencing
systems, and there is no question that you must be patient and persistent
in may cases because even the phone company personnel are not all really
up to speed on ISDN. Somebody at the telco knows, you just have to find
them! It is gaining momentum however, driven by people (and companies)
like ourselves who want it for Internet access and Video.


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
DisplaySubject: Re: ISDN