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.

More Networking Protocols and Standards:
• IPv4 Datagram Fields
• Looking at the OSI 7 Layer Reference Model
• Basic TCP/IP Networking
• Ports and Sockets
• Free eBook: Introduction to 802.11 Wireless
• The OSI Session Layer
• RIP (Routing Information Protocol)
• Video Streaming Protocols
• Video - The Upper Layers 5 Through 7 of the OSI Networking Model
• Routing Information Protocol (RIP), Open Shortest Path First (OSPF), and Routing Convergence

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