DSL is short for the Digital Subscriber Line. It is a medium to provide internet access by transmitting digital data through a phone line. In a DSL connection, you can use both the internet and the telephone line simultaneously. This is primarily used in residences and small businesses that require ease of access to both the internet and the phone lines.

Generally, you can connect to the internet via a few selected options. One is the regular modem that uses LAN (local area network), and another option is the cable modem. But the most versatile is undoubtedly the Digital Subscriber Line (DSL) technology. The bit rate range of a consumer DSL can be from 256 Kbit/s to over 100 M/bit. But there can be various factors which can influence this rate, as such as line condition, DSL technology and service level implementation. The gauge of the copper wire is another factor. The heavier 24 gauge wire carries the same data rate farther than the 26 gauge wire. If someone lives beyond a 5.5 KM range, then the network connectivity depends on whether the service provider will provide the connection through fiber optic cables or not.

Researchers in BELL Labs have reached a broadband speed of 10 Gbit/s using the traditional copper wires. A survey in 2012 has found that DSL was the dominant technology to access broadband with 364.1 million subscribers worldwide. DSL connects through USB ports. To access the internet via DSL, you must connect to a DSL specializing Internet Service Provider (ISP). The provider in question will provide you with a DSL modem which can be connected to a router or a computer. Implementations of DSL can be either Asymmetric DSL (ASDL) or ISDN Digital Subscriber Line (IDSL).

Symmetric DSL (SDSL) splits the upward and downward streams evenly, providing equal speeds to both send and receive data. However, in most cases, the users like to download more data than to upload. So in those cases, the service providers offer Asymmetric DSL (ADSL) service. ADSL service offers a wider frequency range for downstream transfers, which tends to offer downstream speeds which are several times faster. Theoretically, an SDSL connection may provide 2 Mbps upstream and downstream while an ASDL connection may offer 20 Mbps downstream and 1.5 Mbps upstream.


  • The speed is far better than that of normal modems.
  • You can use the internet and the phone line at the same time.
  • DSL technology doesn’t require new wiring, as it uses the existing phone line that you already own.
  • Service providers provide the DSL modems.
  • You can choose between different connection speeds and pricings from various providers.
  • It is cheaper than cable connections.


  • DSL connection works better when the PC in question is nearer to the provider’s office.
  • DSL connection receives data faster, but it lacks speed during transmission.
  • Availability is an issue in remote areas.

Transmission methods can vary depending on the region, the carrier, the market, and the equipment. These are 2B1Q, CAP (Carrier less Amplitude Phase Modulation) and TC-PAM (Trellis Coded Pulse Amplitude Modulation). The most common kind of all these transmission methods is called DMT (Discrete MultiTone modulation).