Omni 56K USB Lite
H
Glossary
Denial of
Service
Act of preventing customers, users, clients or other machines from accessing
data on a computer. This is usually accomplished by interrupting or
overwhelming the computer with bad or excessive information requests.
Digital
The use of a binary code to represent information, such as 0/1, or on/off.
Digital
Loopback Test
A modem test procedure that transfers the received digital data back to the
modulator and transmits them out.
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signed document, the signature is no longer valid.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.
DIP Switch
Dual inline package switch. DIP switches are abundant in the world of
electronic equipment. They are used to set certain parameters on a printer,
modem or other peripheral devices. No DIP switches can be found in ZyXEL
modems. ZyXEL modems let you perform all settings from the front panel or
through command sequences.
DLE
The ASCII code that is used in voice data mode to separate data segments
from command segments.
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.
