Digital Subscriber Line is a family of technologies that provides digital transmission over the wires of a local phone network. DSL originally stood for digital subscriber loop. DSL service is delivered at the same time with consistent phone call services on the same phone line as it utilizes a higher frequency band which is divided by filtering.DSL is a fast wired internet service.

It provides quick networking over normal telephone lines using broadband modem technology. DSL technology permits internet and phone service to work over the same telephone line without requiring shoppers to disconnect either their voice or internet connections. DSL services are used basically in houses and smaller businesses. DSL service works over a limited physical distance and remains unavailable in several areas where the local phone structure doesn't support DSL technology.

The transmission of information in DSL services typically ranges from 384 KB/s to 20 Mbit/s in the direction to the buyer, dependent on DSL technology, line conditions, and service-level implementation. Generally the passage of information towards the service supplier is lower, therefore it is designated as asymmetrical service, but the download and upload speeds are equal for the Symmetric Digital Subscriber Line (SDSL) service. DSL uses a second higher frequency band (larger than 25 kHz) above the low frequency regime (5 kHz and below) utilized by voice communications.

On the client grounds, a DSL filter is installed on each conduit for phone handsets to get rid of the high frequency band, junking interference with the operation of the phone set, and enabling concurrent use. The most common kind of DSL in the United Kingdom, ADSL, splits a single phone line into separate voice and information channels, permitting you to make a telephone call while browsing the internet at the very same time. ADSL is really capable of delivering speeds as much as 8Mbps (Megabits per second) when downloading and 448Kbps (832Kbps on shorter lines) during uploading.

The technology is inexpensive, fast and fairly trusty, though performance can suffer due to ISP congestion, distance from the local exchange (shorter lines = quicker connections, anything over 6.5Km is generally slow) and interference. Each connection is fixed to a particular phone line, which means you can only access your connection from the location where it was installed. The newest ADSL2+ (ITU G.992.5) technology is really capable of pushing download speeds at almost 24Mbps and uploads at nearly 1.4Mbps, it also supports port bonding (links a few lines together for quicker speeds) and has a better range over ADSL.

Both ADSL and ADSL2+ are "best effort" broadband services, suggesting that bandwidth is shared between many users and can be highly variable - particularly over long distances.