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CATION DEVELOPMENT

Pace 605

PC WEEKNAPPLI
MARCA 27, 1989 A MTIDNCE

APPLJED INTELLIGENCE — GO

- Broadband ISDN: High-Speed Information Highway

ital rjetwork. Initially, the very:high-ca- | pacity, fiber.optic circuits to carry all

at speeds between 100M and 565M bps. dptical fiber cireuita a from a few

pacity types of traffic at speeds

| oe A Whil K bps is the transmission zah | nillions of bits per
| lea Ho rate [oe z stavdard digital communica- transmission capacity of pese ge ze ia seti ote s.
| rt series on tion circuit, higher-bandwidth circuits per second are being used on 'ong Ni The "information highway" is a single
Tnte ated Ser- are needed to handle traffic as it passes  tance routes to carry JE ei peli z on network to which users have
ona Digital through the network. Using the tech: traffic centers such as the large cities on  Comm for ali voice, data, text and video
Našlori 'nigues of Pulse Code Modulation and the east, and west coasts of America. access 10 ceh urejenih veki
| (ISDN) a com- | time-division multiplexing, different — As the cost of optical-fiber technolo- pna  SDN neto vili KpeO
mamication tech z ke ooo o erer kk di 41 PRE ji oka ornvertad to pi ali existing networks, giving users access
eo eti Mao Mi ate higher-bandwidth ing T carriers are being COI red o aa x Še
pse vana zRERM REŠI, sj ket. thus boosting their transmission toa Mesa IM A ža kilo ve
tegic impor- In North America, the various multi- capacity. Sle tu ŠE keč ap lize ic an rpo |
At po A A et cona s TI. Tni ii fi bene sk ee polena js ta, . The concept of a common, single-
Juture. carriers. The most common is T-l. This  tiber-optic trans Ee RTA transmission "pipe" is fundamental to
in consideri carrier uses paired wires with digital ; ' many different channels can be accom transmission Pipe
the cer for TEŠ signal ate spaced every 6,000 feet , modated within a ite TETE RECI ei dejal s ENEJ O, sei ona
NA | i | S e cir- al 1
broadband ser- and has a capacity of eže ms Meli Serie suppo y ted st peso O na

Vere LE 24 separate 64K-bps channels. of wavs ke ze |
a speed ksa "200 to 9,600 Although the T carriers were original. The circuit can be configured to carry " ER, zet Pe a ua ppilcakkona that 4
| and pona Ee aa uareranle ly designed to carry traffic within the — only voice traffic with, in some future. 8 pe nine |
came available, line speed immediatel sega circuits from corporations result- nels operating over a single fiber. Alter- The James Martin Productivi (sea |
increased to 64K bps (eguivalent to - oda in TI and then T-3 circuits be- — natively, the type of traffic could be an information service updated Je |
about 8,000 characters per second) urtaf: available to them to lease as mixed; that is, some 64K-bps circuits for terly, is available through High Prosi |
[O Thanks to technologles such as fiber — North America, 3 ekaa ren pat poe oe AMbPS Clreulte for data, other  ductivity Software [nc, of Marble. O ||
(o spil il posle to transmit informa- | 4AT96M po)" o ts operate at Maher epsed channala for video or tele. head, Mass. (800) 242-1240. For infor- — ||
(ine regon tla ct bla per send) trav o epa, 6 The di oonsiinis of analog net. ie United State and Canada) Treh |].
| Bit rates of a trillion bits per second. ina n rna avate networks, interlink- — works (which resulted in the develop nology Transfer Institute. 741 101 St NE
| will be possible in the NETA, z ole and factories across the coun- ment of separate networks for ei Santa MEAN 90002 (219)" [SK |
preseni, most installations of iber-optic and am ka Jela digital neto A oo not apply to 8305. In Europe, contact Savani, 2 si
ems in corporate networks opera « zma KRA 8 orks. A common information New St, Carnforth, Lancs, LA5 9B) |
operate T carriers form the backbone of a dig- highway can be developed using high-ca- nitedi | Kid (sa) V a |
2 | |

vices, the available bandwidth under a
digital communication system such as
ISDN is much greater than with a pre-

bandwidth of G4K bits per second, al-
though bandwidths available with fiber

network traffic (voice is, by far, the
largest proportion), the demand for data
communications is rising rapidly. To ful-
fill this demand both now and in the fu-
ture, networks must be available that
facilitate rapid growth in data commu-
nications at the lowest possible cost. The
best. way to do this is through the use of
digital switching and high-bandwidth
transmission networks.

The growing availability of high-band-
width circuits is having a tremendous
impact on users. Corporations that pre-
viously used voice-grade analog circuits
for computer-to-computer communica-
tions were freguently restricted to a

AI Users Can Access

Eventually, a single ISDN network will replace

;

ih aja
ali existing |

networks, giving users access to a universal "information :
highwajy" for all domestic and corporate communications.

T-1 carrier has the capacity to transmit

cuit can be configured in a wide variety

highway is limited to a transmission
speed of 1.544M bps in North America
and Japan, and 2.048M bps in Europe,

NE nana s analog networ< la tle CU In a Single ISDN thereby limiting the number of 64K-bps
rent implementation of ISDN, the basic ; nele available to čither Ž9 0x 90
| channel available to all users has a channels aval meli

The Next Generation

| re oraslierabi leraer Universal Information The next generation of broadband
e As copper wires in the telephone net: ISDN will use roto b te MAKI SKI.
z work are progressively replaced with fi- systems to link users with the networ
s |... beroptic cables, bandwidths available to ne fiber-optic delke upe PE
ANO each subseriber will dramatically in- a huge increase in the amount o ;
4: CI" —erease from G4K bps to RO Re To width available to users. It will be com-

l the network operator, the increased ca- mon for corporations to have access to
1 pacity of a network means that, more circuits operating at speeds from 50M to
i traffic and greater diversity of services '500M bps. When circuits such as these
a | can be put into operation—both of are available, the concept of a common
J | which will improve revenue. digital information highway will be the
3 PRI LEK building block of future networks.

|. Data Communications Future broadband ISDN networks op-

U Another aspect of bandwidth and ser- | erating at speeds in excess of 500M bps
v vices relates to the increasing demand se will be constructed of multiple numbers
A for computer data communications. In the future, of 6G4K-bps circuits, creating networks

k | Sending data over an analog telephone both gorporate that provide bandwidth "on demand."

; | line reguires the use of a modem. With and domestic users For example, an ordinary telephone

a digital circuit, all the user needs to will access voice, Midi. o 4 call reguires a single 64K-bps circuit.

5 | connect a computer to the telephone lje sd dah The transfer of a large ile (dodatni |
Fo] network is a standard telephone plug data, video and text O a ta Hihi,

| | and the appropriate communications on the same highway tion oraniic and ide) ze ru agen
[: hardware and software in the computer. worldwide. EIR v ba A ea zbi

While data communications still ac- | much as 50M bps. A co Sem
ua ll, counts for only a fraction of the total FE zak ps. A common informa-

tion highway can easily accommodate
both reguirements. Both high- and low-
speed data can travel over the same
network, leaving it up to the user or the
application itself to determine how
much bandwidth is reguired.
- One of the most important aspects of
ISDN as presently configured is that it
iste a Z a for future network de-
veilopment. However, a major problem is
its limited bandwidth. The leoificajie z
of the current implementation is that it
has promoted the creation of a base set,
of standards upon which future broad-
band networks will be developed.

Next week, we will look at the specif-