CO!MUNICATIONS
SECTION 6. 7
6,7,6,3, 1
6,7,6,3,2
6,7,6,3,3
VER.V09F
Blocks of data loaded by LINPUT statements are terminated by CR,
as are lines of printout. The most straightforward method of
block creation is to treat data between CRs as cards of data.
Transmitting Cards
On transmit, if a CR is detected in the data, the communication
software will treat it as a record end. The action taken
depends upon the amount of room left in the current buffer being
prepared for transmission,
For further details on end of record action see section 6,7,6,5,
Sending the last Card
To maintain compatibility with existing transmission programs it
is essential they should operate without modification, This
leaves a problem of how to send the final message buffer if it
has not been filled up. If greater than 5 seconds elapses
between characters sent from the Basic applications program,
then the end of a complete transmission sequence is assured and
the current block terminated by ETX CRC, After this has been
acknowledged the EOT (end of transmission) is sent to close down
the line,
Receiving Cards
The computer generating data for transmission to HUNTER will
also block data into records,
To provide application programs with "CR" delimiters, any end of
record is converted to CR, The end of record will depend upon
the configuration in use, The sequences IUS CRC and IRS will
always return CR,
This means that HUNTERS will communicate directly when connected
back to back,
BSC receiving stations use ESC sequences for special functions
like skipping line, These sequences are ESC n where n can be a
number of printable characters. To avoid confusion when these
are received HUNTER will ignore received ESCs and their
associated following character.
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