3Com 520 - Manual (Page 84)

C-4 C H A P T E R C: G L O S S A R Y
Datagram A message that is sent from one
computer or device to another to confirm it location
or status on a network.
Data link layer The second layer of the OSI
reference model. This layer is responsible for
controlling message traffic.
Data packet (packet) A sequence of binary digits,
including data and control signals that is transmitted
across a LAN or WAN.
DCE Data circuit-terminating equipment.
DTE Data Terminal Equipment. The physical
interface and link access procedures between DTE
and data circuit-terminating equipment (DCE).
DTMF Dial tone multi-frequency, the signalling
system used by PSTN. Refer to PSTN .
Downloading A user initiated transfer of data from a
server to the user’s own workstation. Also used to
classify the transfer of files from one system to
another, usually to upgrade or revise system
software.
EPROM Erasable programmable read-only memory.
A chip whose memory can be erased and reused.
Ethernet A 10 Mbps baseband local area network
protocol, compatible with IEEE 802.3 standards.
FastConnect The OfficeConnect Remote’s
proprietary connection protocol that allows fast
connection between units either over the ISDN link
or over a permanent leased line WAN link.
Fiber optics A technology that uses laser light
pulses, sent over thin glass fibres, which is able to
deliver data at speed up to several gigabits per
second.
File server A computer running a special operating
system that allows workstations to access files.
Filter A configuration that removes types of data
frames based on user-entered parameters.
Firewall A method of preventing unauthorized
access to a network or a host on a network. A firewall
is usually implemented within a router’s software.
Rc.bk : GLOSSARY.FRM Page 4 Thursday, July 10, 1997 9:53 AM