What is dsl internet?. Short for “Digital Subscriber Line”, DSL is a communications medium used to transfer digital signals over standard telephone lines.
Along with cable Internet, DSL is one of the most popular ways ISPs provide broadband Internet access.
When you make a phone call using a landline, voice signals are transmitte using low frequencies from 0 Hz to 4 kHz.
This range, called the “voice band,” uses only a small part of the frequency range supported by copper telephone lines. Therefore, DSL makes use of higher frequencies to transmit digital signals, in the 25 kHz to 1.5 MHz range.
While this frequency is higher than the highest audible frequency (20 kHz), it can still cause interference during telephone conversations.
Therefore, DSL filters or splitters are use to ensure high frequencies do not interfere with telephone calls.
Symmetric DSL (SDSL)
Symmetric DSL (SDSL) divides upstream and downstream frequencies evenly, providing the same speed for sending and receiving data.
However, since most users download more data than they upload, ISPs typically offer asymmetric DSL (ADSL) service. ADSL provides a wider frequency range for downstream transfers, offering several times faster downstream speeds.
For example, an SDSL connection might provide 2 Mbps upstream and downstream, while an ASDL connection might offer 20 Mbps downstream and 1.5 Mbps upstream.
To access the Internet using DSL, you must be connect to a DSL Internet service provider (ISP). The ISP will provide you with a DSL modem, which you can connect to your router or computer.
Some DSL modems now have a built-in wireless router, which allows you to connect to your DSL modem via Wi-Fi. DSL kits may also include a splitter and filter that you can connect to a landline.
NOTE: Because DSL signals have limited coverage, you must live within a certain distance of your ISP to be eligible for DSL Internet service.
While most urban locations now have access to DSL, it is not available in many rural areas.
DSL Modem
Requires a DSL modem. A DSL modem is a device that converts data from a digital signal into a voltage signal that is use by a computer in the appropriate frequency range and then connected to a telephone line.
DSL Protocol and Its Configuration
DSL implementations are capable of creating routed or bridged networks. Groups of user computers are connected to a single subnet in a routed/bridged configuration.
Early implementations of DHCP to provide network details such as IP addresses to user devices, by authentication via MAC addresses or assigning host names.
Later implementations often use PPP over Ethernet or ATM (PPPoA or PPPoE).
Example of DSL Technology
The following are examples of DSL technology (commonly called xDSL) including:
- HDSL (High-bit-rate Digital Subscriber Line), covered in this article
- SDSL (Symmetric Digital Subscriber Line), a standardized version of HDSL
- ADSL (Asymmetric Digital Subscriber Line), a version of DSL with a slower upload speed
- RADSL (Rate-Adaptive Digital Subscriber Line)
- VDSL (Very-high-bit-rate Digital Subscriber Line)
- VDSL2 (Very-high-bit-rate Digital Subscriber Line 2), an improved version of VDSL
- G.SHDSL (G. Symmetric High-speed Digital Subscriber Line), a standardized replacement for early. proprietary SDSL by the International Telecommunication Union Telecommunication Standardization Sector.
Advantages of DSL
- A fairly simultaneous connection between the internet with voice or fax via telephone cable.
- Data security is well maintained.
- Has high access speed and is always online.
- The use price is cheap, especially for residential areas.
Disadvantages of DSL
- Long copper cable from CO to customer.
- There are load coils and bridged taps.
- The third obstacle is fiber optics.
