3Com AccessBuilder 500 User Manual page 106

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PPENDIX LOSSARY
D Channel A control channel carrying signalling information, running
at 16 Kbps. The basic rate ISDN 2 service carries two B channels plus
one control D channel. Refer to ISDN and B Channel.
Data Characters or code either entered by the user or passed between
devices that are part of the computer or network.
Data communications The transfer of data via transceiver equipment by
means of data transmission according to a protocol. Refer to Protocol.
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.