6100 BSC Programming Manual

6100 BSC Concepts and Context
and must be in the range 0 through 32767. The default value, 0,
means no blocking will occur.
BSCITBSIZE has no meaning for normal text. Nor does it come into
play when BSC receives transparent text. The message formats and
protocol associated with transparent text were described in this
section, under the heading "Transparent Text."
BSCSYNCS<n>. This parameter specifies the number of SYN
characters to start each transmission. The value can range from
3 to 255, and includes the initial pad character. The default
value is 3. For more information on the SYN pattern, see
"Message Formats" in this section.
BSCSLRC8. This parameter specifies the use of LRC (Longitudinal
Redundancy Checking) as the block check sequence. This kind of
block checking is suitable only for ASCII data, because it uses
the eighth bit of each character as a parity bit. The other kind
of block check sequence is CRC16, which is required for EBCDIC
data and may also be used for ASCII. You must use CRC16 for
ASCII if you send or receive transparent text. An LRC sequence
is eight bits long; a CRC16 sequence is sixteen bits long. By
default, CRC16 is used.
In addition to the block check you set with this parameter,
BSC checks each ASCII character for odd parity (VRC).
This kind of checking cannot be performed on EBCDIC data.
CHARACTER CODE. The following parameter determines the
character code:
BSCASCII. This parameter specifies ASCII as the character
code. By default, the character code is EBCDIC. BSC has a
standard pair of ASCII<->EBCDIC translation tables. An
application can replace those tables to meet special
requirements.
Even if the line uses EBCDIC, the application uses ASCII for its
data and special characters. BSC translates the output buffer
from ASCII to EBCDIC, and translates data arriving on the line
from EBCDIC to ASCII. Only transparent text is not subject to
translation.
If ID exchange is required on an EBCDIC line, the application
uses the following sequences for ACK 0 and WAK:
• For ACK 0, use 10 hexadecimal (DLE) followed by BA hexadecimal
• For WACK, use 10 hexadecimal (DLE) followed by 2C hexadecimal
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