Glossary

DBS - See direct broadcast satellite.

dedicated connection - A communication link that operates constantly.

dial-up connection - A data communication link that is established when the communication equipment dials a phone number and negotiates a connection with the equipment on the other end of the link.

digital signal - A signal that takes on only two values, off or on, typically represented by "0" or "1." Digital signals require less power but (typically) more bandwidth than analog, and copies of digital signals can be made exactly like the original.

digital subscriber line (DSL) - A data communications technology that transmits information over the copper wires that make up the local loop of the public switched telephone network (See local loop).) It bypasses the circuit-switched lines that make up that network and yields much faster data transmission rates than analog modem technologies

digital subscriber line access multiplexer (DSLAM) - A device found in telephone company central offices that takes a number of DSL subscriber lines and concentrates these onto a single ATM line.

direct broadcast satellite (DBS) - A broadcast technology that uses satellites orbiting the Earth to broadcast television or data signals to an 18" dish antenna.

discrete multi-tone modulation (DMT) - A method of transmitting data on copper phone wires that divides the available frequency range into 256 sub-channels or tones, and which is used for some types of DSL.

discrete wavelet multitone (DWMT) - A variation of DMT modulation that improves performance by using wavelets rather than tones to provide additional isolation of sub-channels.

DMT - See discrete multi-tone modulation.

DNS - See domain name system. domain name system (DNS) The protocol used for assigning text addresses (such as www.2wire.com) for specific computers and computer accounts on the Internet.

DSLAM - See digital subscriber line access multiplexer.

DWMT - See discrete wavelet multitone.