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Prestige 100L IDSL Router
Glossary C
which 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.
Digital
Signature
Digital code that authenticates whomever signed the document or software.
Software, messages, Email, and other electronic documents can be signed
electronically so that they cannot be altered by anyone else. If someone alters a
signed document, the signature is no longer valid. Digital signatures are created
when someone generates a hash from a message, then encrypts and sends both the
hash and the message to the intended recipient. The recipient decrypts the hash and
original message, makes a new hash on the message itself, and compares the new
hash with the old one. If the hashes are the same, the recipient knows that the
message has not been changed. Also see Public-key encryption.
DMS The name of digital central office switches from Northern Telecom. Model numbers
start with BCS.
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, 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 that 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, 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 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, the DTE (data terminal equipment) meant a dumb terminal or printer, but
today it is a computer, or a bridge or router that interconnects local area networks.
EMI
ElectroMagnetic Interference. The interference by electromagnetic signals that can
cause reduced data integrity and increased error rates on transmission channels.
Encryption The act of substituting numbers and characters in a file so that the file is unreadable
until it is decrypted. Encryption is usually done using a mathematical formula that
determines how the file is decrypted.