To: jvncnet!well.com!vrex@dowv
cc: online-news@marketplace.com
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On Thu, 6 Oct 1994 jvncnet!well.com!vrex@dowv wrote:

> Is anyone actually using ISDN? I've heard that Web Browsers a la Mosaic are
> heating up the demand for ISDN, but is it actually here yet?
ISDN is useful if you already have an ISDN capable PBX.  The advantage is
that it takes about 1/4 second to set up a call.  The TCP/IP connection
can then be supported via PPP, and the transfer conducted.  During idle
periods, the line goes quiet.  SUN has ISDN capable hardware and sells the
expansion software.
 
> At 64k-112k it is faster than our leased line and promises great new
> possibilities for Online publishers.I've heard that PacTel is offering it
> cheap and NYNEX service people actually seem to know what ISDN is.
Most corporations are going T1 or Fractional T1 with Frame Relay or ATM. 
You get bandwidth from 128k to 1.5m and can lash it directly to the LAN
using router hardware from Cisco, Wellfleet, et. al.

Residential customers are more likely to see cable or high speed ATM
telephone service than ISDN simply because of the buffering costs of
maintaining loaded virtual circuits.  ISDN gives you access to other ISDN
hosts.  TCP/IP gives you access to 25 million internet hosts.

The telcos have been trying to wire "the last quarter mile" for about 15
years now.  They are now down to "the last hundred feet".  The biggest
problem is that you need a $200 "Feature phone" instead of the $20 analog
phone.  Then you need an ISDN CSU to get to the telco.  The telco has to
replace your 2 wire link with a 4 wire link.

> At the UNIX Expo in NYC, Panix announced that they will begin offering ISDN
> service in 8 weeks and PSI is already offering it.
NYNEX has been offering ISDN access for several years now.  There were
some Inernet POPS that could be accessed before.  The good news for the
POP is that they can replace 24 modems/terminal server ports... with one
T1 interface and ISDN card.

The phone company also likes ISDN.  When you dial-up on an "analog circuit",
the wave form generated by your modem is converted to a digital stream at
8000 samples/second.  Each sample has 7 usable bits.  This digital stream
must flow even when you are just sitting there reading the screen or
thinking about what to type next.  This must be maintained throughout the
entire network.

With ISDN, Frame Relay, or ATM, you send bytes when you are actually
transferring data.  Between keystrokes, someone else can use the physical
links within the network.  When you download the GIF file, you can get
full speed from the line, nearly 128 Kb/s.  If you like, you can add
circuits and let TCP/IP multiplex/demultiplex the packets at rates in
multiples of 128 Kb/s. 

Tarriffs vary.  In most cases, there is a connect charge, a monthly
recurring charge, and a per kilopacket rate.  Here, it's about $300
initial charges including processing fees, connect charges, and about
$30/month for the connection.  Add about $400 for the "modem" (actually
a digital interface card and software).

> James C. Kim @ New York City

	Rex Ballard @ Princeton New Jersey

 



From rexb Thu Oct 27 14:03:47 1994