DSL
Digital Subscriber Line
(pronounced: D-S-L or diesel)
A telecommunications line that provides a fast, permanent connection to the Internet. DSL uses the copper wiring found in almost every home and office. Special hardware attached at both ends of the line allows data to transmit at a far greater speed than standard telephone wiring can. It also provides a constant connection to the Internet, 24/7, so there is no need to dial-in to an ISP each time you want to get online (see: always-on). A DSL line is also convenient because you only need one line to carry both voice and data signals (in other words, you don't have to get a second phone line with DSL). DSL is similar to ISDN in that they both operate over existing copper telephone lines (POTS) and require short runs to a central office. (The reason why DSL is not yet available in many areas is because of the distance from a central office.) DSL provides higher speeds than ISDN, but with DSL, the connection speeds vary. Many people prefer the fixed speed of an ISDN (or a T1, for that matter). Connection speeds for DSL typically range from 1.544 Mbps to 512 Kbps downstream and around 128 Kbps upstream. There are several types of DSL, and xDSL refers to the family of digital subscriber line technologies.
Dial-Up
A dial-up line is a telecommunications medium that links computers using regular telephone lines, generally referring to the kind of connection one makes when using a terminal emulator and a regular modem.
T-1
A T-1 leased line is a high-speed digital line that provides data communication speeds of 1.544 megabits (T-1) per second. Compare 56K and ISDN lines. A T-1 line actually consists of 24 individual channels, each of which supports 64Kbits per second. Each 64Kbit/second channel can be configured to carry voice or data traffic. Most telephone companies allow you to buy just some of these individual channels, known as fractional T-1 access.
Wireless
Communication that takes place via airwaves as opposed to cables or telephone lines. Specifically, wireless communication is enabled by packet radio, spread spectrum, cellular technology, satellites, and microwave towers, and it can be used for voice, data, video, and images. The convergence of wireless networks and computer networks has begun as Internet technology continues to develop and operate over a variety of networks. Fixed wireless refers to wireless devices or systems that are situated in fixed locations, such as an office or home, as opposed to devices that are mobile, such as cell phones or PDAs. Fixed wireless devices normally derive their electrical power from utility mains, but portable wireless devices normally derive their power from batteries. The advantages of fixed wireless include the ability to connect with users in remote areas without the need for laying new cables.
Related Links:
Net Lingo
The Internet Dictionary
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