7. PASTDECADE HAS SEEN EXTENSIVE GROWTH IN THE
TELECOMMUNOCATION INDUSTRY
POPULARITY
OF INTERNET & OTHER DATA
COMMUNICATION SERVICES HAS INCREASED
MAJORITYOF INTERNET USERS ACCESS THEIR SERVICE
VIA MODEMS CONNECTED TO P.O.T.S.
P.O.T.S.
WAS DESIGNED FOR VOICE TRANSMISSION AT
FREQUENCIES BELOW 3 KHz
7
8. TOINCREASE PERFORMANCE OF NEW ONLINE
SERVICES, THE BANDWIDTH HUNGRY PUBLIC MUST
CONSIDER OTHER OPTIONS
TECHNOLOGIES,SUCH AS I.S.D.N. OR CABLE
CONNECTIONS, REQUIRE SPECIAL CABLING
AP.O.T.S. CONNECTION PROVIDED AN ADEQUATE
MEDIUM FOR RELATIVELY SMALL AMOUNTS OF DATA
THAT REQUIRED TO BE TRANSMITTED
SOTHE EXISTING SYSTEM WAS THE LOGICAL CHOICE
OVER SPECIAL CABLING
8
9. H.D.S.L.
IT IS THE PIONEERING HIGH SPEED FORMAT,
BUT NOT COMMERCIALLY VIABLE OPTION DUE TO ITS NEED FOR
2 TWISTED PAIRS &
DOESN’T HAVE SUPPORT FOR NORMAL TELE PHONE SERVICES
S.D.S.L.
IT IS SYMMETRIC DSL
OPERATES OVER A SINGLE TWISTED PAIR
LIMITED TO SHORT DISTANCES
SUFFERS N.E.X.T.
I.S.D.L.
STANDS FOR I.S.D.N. DSL 9
10. SIMILAR TO I.S.D.N. TECHNOLOGY
LACKS SUPPORT FOR ANALOG VOICE
V.D.S.L.
VERY HIGH BIT RATE D.S.L.
REQUIRES
SHORTER CONNECTIONS THAN ARE GENERALLY
PRACTICAL
A.D.S.L.
MOST PROMISING TECHNOLOGY
SUITABLE FOR PERSONAL BROADBAND REQUREMENTS
ALLOWS SAME CHANNEL TO STILL ACT AS A TRADITIONAL
SERVICE 10
11. A MODEM TECHNOLOGY
CONVERTS EXISTING TWISTED PAIR TELEPHONE LINES
INTO ACCESS PATHS FOR MULTIMEDIA & HIGH SPEED
DATA COMMUNICATIONS
CAN TRANSMIT UPTO 6Mbps TO SUBSCRIBER
832 Kbps IN BOTH DIRECTIONS
EXPANDS ACCESS CAPACITY BY A FACTOR OF 50 OR
MORE
ITALLOWS MORE BANDWIDTH DOWNSTREAM THAN
FOR UPSTREAM
11
13. PROVIDESHIGH SPEED INTERNET ACCESS USING
REGULAR TELEPHONE LINES
CONNECTIVITY-ALWAYS ON
DATA SECURITY
EASE OF USE
NO DIAL-UP IS REQUIRED
SPEED
IS UPTO 25 TIMES FASTER THAN ANALOG
MODEMS
13
14. ADSL will play a crucial role over the next decade or more as
telephone companies enter new
markets for delivering information in video and multimedia
formats. New broadband cabling will
take decades to reach all prospective subscribers. Success of
these new services will depend on
reaching as many subscribers as possible during the first few
years. By bringing movies, television,
video catalogs, remote CD-ROMs, corporate LANs, and the
Internet into homes and small
businesses, ADSL will make these markets viable and
profitable for telephone companies and
application suppliers alike.
ADSL Capabilities
16. oADSLMODEM CONNECTED TO EACH END OF TWISTED PAIR
TELEPHONE LINE
o3 INFORMATION CHANNELS ARE CREATED :-
o1). HIGH SPEED DOWNSTREAM CHANNEL
o2). A MEDIUM SPEED DUPLEX CHANNEL
o3). A BASIC TELEPHONE SERVICE CHANNEL
oADSL GUARANTEES UNINTERRUPTED TELEPHONE SERVICE EVEN
IF ADSL FAILS
oDOWMSTREAM RATES DEPEND ON :-
o1). LENGTH OF COPPER LINE 16
23. 1). CARRIERLESS AMPLITUDE / PHASE (CAP)
TELEPHONE SIGNAL DIVIDED IN 3 PARTS
i. VOICE CONVERSATIONS- 0 TO 4 KHz (POTS CKT)
ii. UPSTREAM CHANNEL-25 TO 160 KHz (FROM USER BACK
TO SERVER)
iii. DOWNSTREAM CHANNEL- BEGINS AT 240 KHz (FROM
SERVER TO USER)
INTERFERENCE MINIMISED
25. BLOCK SIGNALS ABOVE CERTAIN FREQUENCY
ALL CONVERSATIONS- BELOW 4 KHz
LPF’s DESIGNED TO BLOCK SIGNALS ABOVE 4KHz
PREVENT DATA SIGNALS FROM INTERFERING WITH
STANDARD TELEPHONE CALLS
25
26. It uses two pc’s of equipments one at the customer end and one at
the internet services provider
Atthe customer location there is DSL transceiver also called as
“DSL MODEM” and ATU-R too.
DSL service provider has a DSL access
multiplexer(DSLAM ) to receive customer connection.
The transceiver can connect to the customer equipment by using
USB or 10 base –T Ethernet connections.
The devices used by businesses may combine network routers
network switches or other networking equipments
27. It really allows DSL to happen
It takes connection from many customers and
aggregates them on to a single high capacity connection
to the internet
It is flexible and able to support multiple types of DSL
in a single central office.
28.
29. IT IS A DISTANCE SENSITIVE TECHNOLOGY.
LIMIT FOR ADSL service is 18000 feet.
Maximum downstream speed is 8 mbps at a
distance of about 6000 feet.
Maximum upstream speed is 640 kbps.
ADSL cant be received using bridge tapes , fiber
optic cables and loading coils. .
30. DSL ADSL
It do not uses the It uses the frequency
spectrum
frequency spectrum
Splitter or micro filter Frequency filters are used at
are used near the customers premises to
avoid interference
demarcation point This do not require
This requires a technician
technician for
installation purposes Less costlier than DSL
More costlier
DSL signal is separated DSL signal is filtered at each
phone outlet by use of LPF
at demarcation point for voice and HPF for data
31. Maximum range for DSL without a
repeater is 5.5 km
As distance decreases towards the telephone
company office , the data rate increases
For larger distances , DSL service is provided
only when phone company has extended the
local loop with optical fiber cable
32. The distance from local exchange
The type and thickness of wires used
The number and type of joins in the wire
The proximity of the wire to other wires carrying
ADSL ,ISDN and other non voice signals
The proximity of the wires to radio transmitters
33. Phone line , activation by your phone company
for it
Filter to separate the phone signal from the internet
signal
ADSL modem
Subscription with an ISP supporting ADSL
36. IT IS ASYMMRTRIC.
ALLOWS MORE BANDWIDTH FOR
DOWNSTREAM THAN UPSREAM
DATA FLOW.
ADSL modems create multiple channels
using FDM or echo cancellation.
It is ideal for those who download
much more data than they send.