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**** The Hebrew University of Jerusalem ****
**** Computation Center ****
News Bulletin #102
9-Jun-1997
Today's topics:
- ISDN
What is ISDN?
=============
ISDN is a new type of phone line which can be installed at
home. The analog phone line usually used can be used only by one
device at a time (phone, fax, modem, etc.); since it uses analog
technology it is quite limited in bandwidth and is not perfect for
digital transmission. Bezeq now offers a full digital line called
ISDN, which contains two 64Kb channels to private residences. Each
such channel can be used to transmit data (instead of a modem call)
or voice. Thus, one channel can be used for data communication
while the second is used for voice, or both channels can be used to
double the data transfer rate (in which case the voice phone is
disabled during that period).
What are the benefits of ISDN?
==============================
The benefits of ISDN as stated above are full 64Kb/sec transfer
rate per channel. Since the line is a true digital one, the error
rate is quite small. Note that the 64Kb/sec rate is for
uncompressed transfer, and once the university's side will support
compression the rate will go even higher.
The line has two channels, which can be used independently for data
and voice. For example, one channel can transmit data while voice
is transferred over the other one, or both channels can be used
simultaneously for data transfer (and voice is disabled during this
time period).
It is possible to get more than one phone number for the same line,
and program each phone connected to it to ring on a different called
number; however, for this special digital ISDN phones have to be
used.
Since the line includes an additional (slow) signaling channel,
information about calls made while all channels were busy is
available.
What are the drawbacks of ISDN?
===============================
Well, as with anything good there are also bad sides: An ISDN
line costs more: 877NIS+VAT for installation, 545+VAT for upgrade
of an existing analog line; The monthly charge rate is two times
that of the analog line. Call rates are the same as for normal
phones (but note that a 128Kb call is counted as two calls). The
analog phone cannot be connected anymore to the line, so a special
phone is needed if that line is to be used for voice calls), the
modem is not used anymore (a special card called TA is used). Bezeq
will sell in the future an ISDN end point which has analog ports, to
which the old phone can be connected (but they are more expensive).
Some of the external ISDN adapters for PCs also have such an analog
connection, so this might also solve this problem.
Note: ISDN lines contain an "end point" called NT1 located at home
which needs an electrical connection. When there is a power failure
the ISDN line is disabled, disabling also analog phones connected to
it.
Why not wait for 56K modems?
============================
56K modems are an option too. However, since they are not yet
widely deployed, we have no idea how they work in real life. Note
that the maximum speed is 56K, and actual speed may be lower. With
ISDN you get true 64Kb/sec with no fall-back to lower speeds. ISDN
also provides two channels (128Kb) if the equipment supports it.
Who should use ISDN
===================
ISDN is intended mainly for those who work extensively via
modems and need to download large quantities of data. Although it
doesn't solve the problem of the slow international line, it allows
for faster downloading of items found at the proxies or local
systems.
ISDN adapter types
==================
The ISDN adapters can be divided roughly into 3 groups:
Internal, external and stand alone.
Internal: These are internal PC cards. They are usually the
cheapest and are used when all that is needed from the ISDN line is
data calls (and the use of an external ISDN phone in case voice
calls are to be transmitted over the ISDN lines). Their biggest
advantage (except for the lower price) is that they are connected
directly to the PC bus, thus can fully utilize the 128Kb of two
channels, and even higher speeds when compression is used. The
drawback is that they need special drivers (which come with the
card).
External: These are external boxes which connect to the PC via a
serial interface. Some of them come with drivers, other simulate a
modem, allowing all standard software to run unchanged. Another
feature on most such adapters is an analog phone socket. The main
drawbacks are that they need an external power supply and that are
limited to the serial connection speed (115,200, and only if you
have a good serial port). On most systems it will be hard to fully
utilize the maximum speed of each channel due to the serial
connection limitations. These adapters are usually more expensive
than the internal ones.
Stand alone (routers): There are devices connected to ISDN from one
side and usually to Ethernet on the other side. They usually
contain analog phone connections, need external power supplies, are
bigger than the others and more expensive. Their main advantage is
that they are connected via Ethernet to the PC (thus need no special
drivers), can utilize maximum speed, and usually have the least
interoperability problems. They are recommended mainly for those
who can afford it, or have a network at home. Note that in the
latter case a special setup is needed on our side, thus you must
coordinate with us before purchasing such equipment.
Macintosh: Macs can connect to either external adapters connected
via a serial connection, or to external adapters connected via the
Geoport, or to internal adapters; since the internal adapters are
for PCI or NuBus, they are quite expensive.
Recommended equipment
=====================
We've checked a few models sold in Israel. Other models are
also sold in Israel, and probably work OK.
Note about prices: Most of the prices are special deals for the
university, so mention that you are a university employee when
ordering.
Teles SO16.3: This is an internal card for PCs and supports only
data connections. It comes with Chameleon for Win-3 (TCP/IP only).
It can be installed on WIN-95 in which case it supports Novell also.
It supports either 64 or 128Kb/sec connections, and from our
experience it is the best purchase for the PC world.
Card Price: $115+VAT from Bitcom.
Package: $380+VAT for card + installation + new line from ThinkCom.
Eicon Diva Pro-2.0: This is an active (has on-board processor)
internal card for PCs which supports data connections; with an
optional adapter (has to be purchased separately) you can connect an
analog phone to it. It supports Windows-3.11, Windows-95 and
Windows-NT. Under Win-3.11 it can be used by Trumpet (and supports
under it only one B channel) while the next version will have a
commercial TCP/IP (OnNet) included. Under Win-95 it supports IP and
IPX, and can use one or two channels. It has also a 14,400 modem
function which allows you to dial via your ISDN line to an analog
modem.
Price: $545+VAT for card + installation + new phone line, from
ThinkCom. A cheaper version of the card (does not include modem or
fax) costs $380 for the same package.
Note: Eicon cards have 5 a year warranty.
Zyxel OmniNet: An external adapter connected via a serial
connection which has two analog phone ports which can be used for
analog telephones or fax. It supports only 64Kb/sec connections,
but has compression (Stacker) which works with some of our equipment
and gives roughly a 50% boost.
It is Available from Bitcom for $308+VAT.
A package containing the adapter, new line and installation costs
$580+VAT from ThinkCom.
Motorola BitSurf Pro: External adapter with two analog phone ports
(which can only accept calls, but cannot initiate calls). It
supports only one 64Kb/sec channel, and was not very reliable;
hence, we do not recommend it.
Price: $505+VAT from Motorola.
Sagem Geoport for Mac: External adapter connected to a Macintosh
via the Geoport. We recommend it only for those models that supply
power via the Geoport. It is a data only device, can work with 64
or 128Kb/sec data rates, and does not have compression. It can work
with one channel (64K) and raise the other one only when needed.
Price: Available from Bitcom for $585+VAT.
DataFire from Digi: Internal card for PC with data ports only. We
do not recommend this card for Win-3 as it uses DOS drivers which
are cumbersome to install and operate. Under Win95 it works OK
(both one and two channels).
It is available from Ligad and costs $298+VAT. Not a good deal for
this price.
Asuscom: Internal card for PC, data only. Has COM port emulation
and CAPI for Win95. It supports one or two channels on both
systems.
Available from Ligad at $125+VAT.
Cisco 201: Internal card for PCs, data only. Under Win-3 uses a
DOS interface, thus it is not recommended.
Under Win-95 it does not have CAPI or COM support, thus you have to
use its own dialer and not the standard Windows dialer. The only
advantages are the compression ability (currently supported only by
some of our access servers) and the ability to raise and close the
second channel by a manual command during the connection.
Available from Sysconet for $124+VAT.
KX Pro ISDN/v.34+: This is an external adapter which has inside a
33.600 modem and has fax capability. There is also a version called
"KX Pro ISDN" which does not have the analog modem and fax
capability. We did not check this box.
It is available from ThinkCom. The ISDN/v.34+ package (including
line and installation) costs $580+VAT, while the same package
without the modem costs $495+VAT.
Contact people
==============
Bitcom: Ofer Skarbin, Tsvi Shani: 08-9407340.
Motorola: Ori Bergman: 03-9274447.
ThinkCom (Machshava Yotseret): Oren Yechezkely: 02-6230070.
Ligad: Eli Ben-Hur: 03-9020510.
Sysconet: Yair Gitelman: 09-9587945.
How to order a phone line
=========================
You have two options: Ordering a new line for 877 NIS+VAT, or
upgrading your analog line to an ISDN one at 545 NIS+VAT. Currently
the line is supplied with an end-point (called NT1) that supports
only ISDN devices (i.e. PC cards, special digital phone, etc.). In
the future, there will be a hybrid NT1 which has also has analog
phone ports to which you can connect a standard phone. When this is
available it will be possible to replace the current NT1 with the
new end-point by paying only the price difference.
For a limited period of time Bezeq offers special prices only for
Hebrew University employees only:
Orders arriving until 15/7/97: 250NIS discount.
Orders arriving from 16/7/97 to 15/8/97: 150NIS discount.
Orders arriving from 16/8/97 to 15/9/97: 75NIS discount.
Note: Bezeq cannot supply ISDN lines in all areas. The special
deal is only for those that live in places where Bezeq can supply
the lines now.
To order the lines under the terms of this deal, please use the
special phone number provided for it: 1-800-230230.
__Yehavi:
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