ZyXEL Communications Prestige 724, Руководство пользователя

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Prestige 724 G.SHDSL CSU/DSU
Glossary I
Domain Name The unique name that identifies an Internet site. Domain Names always have two or
more parts that are separated by dots. The part on the left is the most specific and the
part on the right is the most general.
DRAM Dynamic RAM (Random Access Memory) stores information in capacitors that must
be refreshed periodically.
DSL Digital Subscriber Line technologies enhance 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, meaning 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 Multiplexor (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. Interference by electromagnetic signals that can cause
reduced data integrity and increased error rates on transmission channels.
Encapsulation Encapsulation is the inclusion of one data structure within another structure so that
the first data structure is hidden for the time being.
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 FCC (Federal Communications Commission) is in charge of allocating the
electromagnetic spectrum and thus the bandwidth of various communication systems.
Flash memory
A nonvolatile storage device that can be electrically erased and reprogrammed so that
data can be stored, booted and rewritten as necessary.