with other BSC-adapted stations and terminals, thus
providing the following
cations capabilities:
with powerful error-detection capabilities.
Interchange Code.
Code for Information Interchange (formerly
called
Information Interchange).
w hen operating in transparent mode.
two packed-decimal digits in a given character
unedited information.
networks with station-selection features.
Autocall feature) and automatic answering of
cations networks using a contention system.
operations in
mission.
adaptable to the user's requirements.
Base and Synchronous Features, to the multi
plexer channel of the
75 via the IBM
communications attachments with another
Synchronous-Feature-equipped IBM
an
to an IBM
with ICA Feature, or to an IBM
puting
GENERAL
operations use circuitry provided by the basic
Features. For reading ease, therefore, references
in this publication will be to Synchronous Features
The
its associated control-character repertoire.
(Understanding the difference between a
a "data-link control" procedure is important. A
code--such as EBCDIC,
bit configurations having meaning to a circuit, or
a program. As such, it can be compared to a word
in the English language.
sequencing of the coded characters. This sequencing
can be compared to the English grammar that deter
mines the sequencing of words in the language. )
This data-link procedure (and associated repertoire)
provides a
language,
aspects of data transmission:
Establishment of communications through-
Contention (point-to-point system control);
Multipoint control operations (selection and
polling);
Switched-network operations (automatic answer
ing and automatic disconnect).
Message transmission--
Message-exchange operation (heading and text
transmission);
Data blocking;
Transmission-error checking;
Station-status replies;
Enquiry functions and alternating replies;
Transparent-data transmission.
The basic control of the transmission link between
two BSC-adapted items of equipment is accomplished
by the recognition of the data-link-control character
in conjunction with established equipment-generated
timeouts. All transmission over the data link is a
binary-bit stream and is synchronous by bit
character. Bit synchronism is established by the
modem (data set), or by an optional internal clock
47