ZyXEL Communications Prestige 782R, User Manual, Page: 151 / 166

Prestige 782R G.SHDSL Router
D Glossary
means that addresses are made available to assign to other systems.
Digital The use of a binary code to represent information, such as 0/1, or on/off.
DNS Domain Name System. A database of domain names and their IP addresses. DNS is
the primary naming system for many distributed networks, including the Internet.
Domain Name The unique name that identifies an Internet site. Domain Names always have 2 or
more parts that are separated by dots. Generally speaking, the part on the left is the
most specific and the part on the right is the most general.
DRAM Dynamic RAM stores information in capacitors that must be refreshed periodically.
DSL Digital Subscriber Line technologies enhances the data capacity of the existing
twisted-pair wire that runs between the local telephone company switching offices and
most homes and offices. There are actually seven types of DSL service, ranging in
speeds from 16 Kbits/sec to 52 Mbits/sec. The services are either symmetrical (traffic
flows at the same speed in both directions) or asymmetrical (the downstream capacity
is higher than the upstream capacity). DSL connections are point-to-point dedicated
circuits which means that they are always connected. There is no dial-up. There is also
no switching, which means that the line is a direct connection into the carrier’s frame
relay, ATM (Asynchronous Transfer Mode) or Internet-connect system.
DSLAM A Digital Subscriber Line Access Multiplexer (DSLAM) is a network device, usually at a
telephone company central office, that receives signals from multiple customer Digital
Subscriber Line connections and puts the signals on a high-speed backbone line using
multiplexing techniques. Depending on the product, DSLAM multiplexers connect DSL
lines with some combination of asynchronous transfer mode ATM, frame relay or IP
networks.
DTE Originally, Data Terminal Equipment meant Dumb Terminal Equipment. But today it is
a computer, bridge or router that interconnects local area networks (LANs) in
increasingly more intelligent ways.
EMI Electromagnetic Interference. The interference by electromagnetic signals that can
cause reduced data integrity and increased error rates on transmission channels.
Ethernet A very common method of networking computers in a LAN. There are a number of
adaptations to the IEEE 802.3 Ethernet standard, including adaptations with data rates
of 10 Mbits/sec and 100 Mbits/sec over coaxial cable, twisted-pair cable and fiber-optic
cable. The latest version of Ethernet, Gigabit Ethernet, has a data rate of 1 Gbit/sec.
FAQ Frequently Asked Questions. FAQs are documents that list and answer the most
common questions on a particular subject.
FCC The Federal Communications Commission is responsible for allocating the
electromagnetic spectrum and thus the bandwidth of various communication systems.
Flash Memory Nonvolatile storage that can be electrically erased and reprogrammed so that data can