An ISDN (Integrated Services Digital Network) capable phone line can provide connection speeds of up to 64Kbps (single channel) or 128Kbps (dual channel) using a terminal adapter often referred to as an ISDN modem [modem: a piece of hardware that connects a computer to the Internet ]. The terminal adaptor removes the need to convert digital [digital: data measured at discrete intervals, eg a digital watch typically moves from displaying one second to the next without displaying the values in-between ] signals to analogue signals before they’re sent down the telephone line, this results in a more reliable Internet connection [Internet connection: a computer's or another internet-enabled device's connection to the Internet ].
ADSL (Asymmetric Digital Subscriber Line) provides connection speeds of up to 24Mbps [megabits per second (Mbps): a measurement of data transfer speed ] and uses a telephone line to receive and transmit data [data: information without context, eg a list of students with numbers beside their names is data, when it's made clear that those numbers represent their placing in a 100 metre race, the data becomes information ].
The speed that data can be transferred is dependent on a number of factors:
An ADSL modem/router [router: a device for connecting computers and other network capable devices together to form a network ] is needed for broadband [broadband: high speed Internet access ] Internet access over ADSL. This is usually provided by your ISP [Internet Service Provider (ISP): Internet Service Provider - needed in order to access the Internet, they also provide services such as web space and email ].
Phone calls can still be made whilst connected.
Cable companies do not use traditional telephone lines to provide broadband Internet access. They have their own network [network: a group of interconnected computers ], a combination of co-axial copper cable and fibre optic cable [fibre optic cable: cable that carries data transmitted as light ].
With their purposefully built infrastructure cable companies are able to provide speeds of up to 50Mbps - considerably faster than the highest available ADSL speed (24Mbps).
A cable modem/router is needed for broadband Internet access over cable. This is usually provided by your ISP.
The making and receiving of phone calls is not affected because the telephone line is not used.