Texas Instruments 990 User Manual page 253

Glossary
GLOSSARY
This appendix contains a glossary of the terms used in this
manual. The definition of terms provided apply specifically to
the OXIO HOLC Communications Package as they are used in this
manual.
Activation services
CCITT
Activation services is a part of the communications package
software for use by applications programs that expect input
data from other stations. A call to activation services is
executed by a level 15 XOP with opcode
>40,
where the I/O
opcode ranges from 4 to 7 and specifies the function to be
performed.
An abbreviation for the Consultative
International Telegraph and Telephone.
standards organization set up to study
The OXIO HOLC Communications Package
X.25/HDLC developed by the CCITT.
Committee for
The CCITT is a
digital networks.
is a subset of the
Communications buffers
Input and output buffers
.package to handle data
network.
Communications line
allocated by the communications
transfers between stations in the
A line consisting of a single shielded, twisted-pair cable
that interconnects the stations in a local line network.
The cable is connected from the.FCCC board in the primary
station to the LLM boards in the secondary stations.
Communications register unit
See CRU.
Communications tasks
Software programs in the communications package included in
both primary and secondary stations that provide
'communications services to the network.
CRU (communications register unit)
The direct command-driven serial input/output interface of
the 990 computer.
2270526-9701 G1ossary-1