DSL is a technology that provides high-speed internet access over ordinary copper telephone lines. It allows data transmission faster than traditional modems. There are different types of DSL including ADSL, VDSL, HDSL, and SDSL. ADSL provides higher download speeds than upload speeds, making it suitable for homes. VDSL and HDSL can provide higher speeds but over shorter distances. SDSL provides equal speeds upstream and downstream, making it more suitable for businesses that transmit large amounts of data in both directions.

1. DSL
(DIGITALSUBSCRIBERLINE)
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2. WHAT IS DSL?
• DSL IS A TECHNOLOGY THAT BRINGS HIGH BANDWIDTH
INTERNET CONNECTION TO HOMES AND BUSINESSES OVER
ORDINARY COPPER TELEPHONE LINES.
• DSL TECHNOLOGY ALLOWS DATA TRANSMISSION AT
SPEEDS MUCH FASTER THAN THE BEST AVAILABLE ANALOG
AND DIGITAL MODEMS.
• WE'LL EXPLAIN A FEW OF THE VARIETY OF DSL
CONNECTIONS BELOW.
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3. DSL
TELEPHONE COMPANIES DEVELOPED
ANOTHER TECHNOLOGY CALLED DSL.
DSL IS USED TO PROVIDE HIGHER-SPEED ACCESS TO THE
INTERNET.
(DSL) TECHNOLOGY IS ONE OF THE MOST PROMISING FOR
SUPPORTING HIGH-SPEED
DIGITAL COMMUNICATION OVER THE EXISTING LOCAL LOOPS
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4. DSL:
DSL TECHNOLOGY IS A SET OF TECHNOLOGIES,
EACH DIFFERING IN THE FIRST LETTER (ADSL,
VDSL, HDSL, AND SDSL).
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5. TYPES OF DSL
 ADSL(ASYMMETRIC DIGITAL SUBSCRIBER LINE)
 ADSL PROVIDE A HIGH BIT RATE IN THE DOWNSTREAM DIRECTION
THAN IN THE UPSTREAM DIRECTION THAT’S WHY IT IS KNOWN AS
ASYMMETRIC DSL.
 ADSL IS SPECIALLY DESIGNED FOR RESIDENTIAL CUSTOMER.
 ADSL IS NOT SUITABLE FOR BUSINESS CUSTOMERS WHO NEED A
LARGE BANDWIDTH IN BOTH DIRECTIONS.
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6. ADSL
• ONE INTERESTING POINT IS THAT ADSL USES THE EXISTING
LOCAL LOOPS.
• THE EXISTING LOCAL LOOPS CAN HANDLE BANDWIDTHS UP
TO 1.1 MHZ
• THERE IS NO SET WAY THAT THE BANDWIDTH OF A SYSTEM
IS DIVIDED.
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7. ADSL:
• EACH SYSTEM CAN DECIDE ON ITS BANDWIDTH DIVISION.
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8. VDSL:
• VDSL STANDS FOR VERY HIGH BIT RATE OF DIGITAL
SUBSCRIBER LINE.
• IT IS SIMILAR TO ADSL USES COAXIAL FIBER OPTICS OR
TWISTED PAIR CABLES FOR A SHORT DISTANCE.
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9. VDSL
• IT PROVIDES A RANGE OF BIT RATE(25 TO 55 MBPS) FOR
DOWNSTREAM COMMUNICATION AT DISTANCES OF 3000
TO 10,000 FT.
• THE UPSTREAM RATE IS NORMALLY
3.2 MBPS.
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10. HDSL
• HDSL STAND FOR HIGH-BIT-RATE DIGITAL SUBSCRIBER
LINE.
• HDSL WAS DESIGNED AS AN ALTERNATIVE TO
THE T-1 LINE (1.544 MBPS).
• THE T-1LINE USES ALTERNATE MARK INVERSION
(AMI) ENCODING .
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11. HDSL
• FOR LONGER DISTANCES, A REPEATER IS
NECESSARY, WHICH MEANS INCREASED COSTS.
• A DATA RATE OF 1.544 MBPS (SOMETIMES UP TO 2 MBPS)
CAN BE ACHIEVED WITHOUT REPEATERS UP TO A DISTANCE
OF 12,000 FT (3.86 KM).
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12. HDSL
• HDSL USES TWO TWISTED PAIRS (ONE PAIR FOR EACH
DIRECTION) TO ACHIEVE FULL-DUPLEX TRANSMISSION.
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13. SDSL
• SDSL STAND FOR SYMMETRIC DIGITAL SUBSCRIBER LINE.
• SDSL IS A ONE TWISTED-PAIR VERSION OF HDSL.
• IT PROVIDES FULL-DUPLEX SYMMETRIC COMMUNICATION
SUPPORTING UP TO 768 KBPS IN EACH DIRECTION.
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14. SDSL
• IN SDSL THE DATA RATE IN DOWNSTREAM DIRECTION AND
UPSTREAM DIRECTION ARE SAME OR EQUAL.
SDSL, WHICH PROVIDES SYMMETRIC COMMUNICATION,
CAN BE CONSIDERED AN
ALTERNATIVE TO ADSL.
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15. SDSL
• ALTHOUGH THIS FEATURE MEETS THE
NEEDS OF MOST RESIDENTIAL SUBSCRIBERS.
• IT IS NOT SUITABLE FOR BUSINESSES THAT SEND AND
RECEIVE DATA IN LARGE VOLUMES IN BOTH DIRECTIONS.
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16. SUMMARY OF DSL TECHNOLOGIES
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