DSL (Digital Subscriber Line)
By Stephen Bucaro
DSL (Digital Subscriber Line) is a technology used to transmit digital data over telephone lines.
The term DSL usually refers to ADSL (Asymmetric Digital Subscriber Line) a technology that enables
digital data transmission over copper telephone lines.
The bit rate of consumer DSL services typically ranges from 256 Kbit/s to over 100 Mbit/s but
actual speeds vary depending on the quality of the copper phone line installation. The length
of the phone line needed to reach the service provider's equipment (sometimes called the
"central office") also can limit the maximum speed a DSL installation supports.
DSL service can be transmitted simultaneously with voice band telephone service on the same line
because DSL uses a much higher frequency that rides on top of the low 3400 Hz voiceband. A
telephone outlet blocks the high digital data frequency to enable simultaneous use of the voice
and DSL services.
DSL has been a common type of Internet service for many years, but the experience of individual
customers can vary greatly depending on their location, their provider, the quality of telephone
wiring in their residence and some other factors.
VDSL (Very-high-bit-rate Digital Subscriber Line) which is available when the site has fiber-optic
cabling and allows speeds up to 52 Mbit/s and 16 Mbit/s and can be used for HDTV.
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