Interphase Tech RAS Communications Controller 5536 User Manual
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Glossary
206
Interphase Corporation
Distributed Function Terminal (DFT)
1) A protocol used for com-
munication between a terminal and an IBM 3270 or IBM 3174 control
unit that allows multiple concurrent logical terminal sessions. 2) A
mode of operation that uses this protocol.
DLC
See data link control.
DLCI
See data link control identifier.
DMA (Direct Memory Access)
A fast method of moving data
between two subsystems without processor intervention.
DMS/DMS100
The name of a central office switch manufactured by
Northern Telecom. These switches use Custom (proprietary) or
National ISDN-1 (NI-1) software.
DSR, data set ready
RS-232 (V.24) interface control signal, sent
from the data communications equipment to the data terminal equip-
ment on pin 6. Indicates that the DCE is connected to the telephone cir-
cuit. Usually a prerequisite to the DTE issuing request-to-send. (See
.)
DSU
See
CSU/DSU (Channel Service Unit/ Data Service Unit)
.
DTE (Data Terminal Equipment)
Equipment serving as the data
source, the data sink, or both. Refers to terminals, computer ports, and
printers. Also interface signals typically presented by this equipment.
DTR (Data Terminal Ready)
RS-232 (V.24) interface control signal,
sent from the data terminal equipment to the data communications
equipment on pin 20. Indicates the DTE is ready for data transmission
and requesting connection of the DCE to the telephone circuit. (See
.)
EIR
Excess Information Rate
EIS
The SNA Server Emulator Interface Specification.
Encapsulation
Process by which an interface device places an end
device’s protocol-specific frames inside a Frame Relay, X.25, or PPP
frame to a frame relay network must perform encapsulation.
ETS
European Telecommunications Standard from ETSI
ETSI
The European Telecommunications Standards Institute
EuroISDN
The European implementation of Q.931, providing a
common standard for ISDN signalling within Europe. Issued by ETSI
under the ETS 300 series standards. Net3(BRI) and Net5(PRI). See