User`s manual
APPENDIX
C
GLOSSARY
OF
TERMS
AND
ABBREVIATIONS
A
CK
-
Acknowledgment
ACK
O.
ACK
I (Affirmative Acknowledgment) -
These
replies
(DLE
sequence in Binary
Synchronous
Com-
munications)
indicate
that
the previous
transmission
block
is
accepted by
the
receiver
and
that
it is ready
to
accept the next block
of
the
transmission.
Use
of
ACK
0
and
ACK
I alternately provides sequential
checking
control
for a series
of
replies.
ACK
0 is also
an affirmative (ready
to
receive) reply
to
a
station
selection (multipoint),
or
to
an
initialization sequence
(line bid)
in
point-to-point operation.
A
SCI
I -
Ameri~an
Standard
Code
for
Information
I nterchange. This
is
the
code
established as
an
Ameri-
can
standard
by
the
American
Standards
Association.
Automatic Calling Unit
(ACU)
- A dialing device
(Bell
801
or
equivalent)
that
permits a business
machine
to
dial calls
automatically
over
the
commu-
nications network.
Basehand - In
the
process
of
modulation,
the
base-
band
is
the frequency
band
occupied by the aggregate
of
the
transmitted
signals when first used
to
modulate
a carrier.
Baud - A unit
of
signaling speed.
One
baud
corre-
sponds
to
a rate
of
one
signal element
per
second.
Thus,
with a
duration
of
the
shortest
signal element
of
20 ms, the
modulation
rate
is
50
baud.
Baudo/ Code - A
code
for the transmission
of
data
in
which five bits represent
one
character. It
is
named
for Emile Baudot, a pioneer in printing telegraphy.
The
name
is
usually applied
to
the
code
used in
many
teleprinter systems
and
which was first used by
Mur-
ray, a
contemporary
of
Baudot.
BCC
- Block Check
Character
(q.v.)
C-l
Binary Synchronous Communications
(BSC)
- A uni-
form discipline, using a defined set
of
control
charac-
ters
and
control
sequences,
for
synchronized
transmission
of
binary
coded
data
between
stations
in
a
data
communications
system.
(Also
called
BISYNC.)
BISYNC
- Binary
Synchronous
Communications.
Block Check Character (
BCC)
-
The
result
of
a trans-
mission verification
algorithm
accumulated
over a
transmission block, and normally
appended
at the
end: e.g.,
CRC.
LRC.
Byte
- A
binary
element string
operated
upon
as a
unit
and
usually
shorter
than
a
computer
word, e.g.,
six-bit, eight-bit,
or
nine-bit bytes.
Carrier - A
continuous
frequency
capable
of
being
modulated
or
impressed with a signal.
CCITT
-
Comite
Consultatif
Internationale
Tele-
graphique
et
Telephonique.
An
international
con-
sultative
committee
that
sets
international
communications
usage
standards.
Channel - (a.) A
path
for electrical transmIssIon
between two
or
more
points. Also called a circuit,
facility, line, link,
or
path.
(b.)
The
physical facility
or
path
plus
control
codes, within which
the
actual
data
to
be
transferred
is
embedded.
Character -
The
actual
or
coded
representation
of
a
digit,
letter,
or
special symbol.
CO
-
Carrier
On.
Communication Control Character - In
ASCII,
a
functional
character
intended
to
control
or
facilitate
transmission over
data
networks.
There
are
ten
con-
trol
characters
specified in
ASCII
which form
the
basis for
character-oriented
communications
control
procedures. (See also:
Control
Character.)