Black Box PROTOCOL CONVERTER A/S-4 - Manual (Page 57)

PROTOCOL CONVERTER MODEL A/S-4
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2) SI (X`0F’) character asks the A/S-4 for the SNA line status of each Logical Unit. The
response to the SI is described in the transmission of the SI character as a special control
character. Any data following the SI character will be thrown away until a Start of File is
received. The SI (X`0F’) character does not need to be preceded by the Start of File
character or followed by an End of File character.
3. Normal ASCII data received from the VDU will be converted into EBCDIC before being
transmitted to the SNA host computer. This received data will be checked for end of record
characters (CR, LF, CRLF and RS) and trailing spaces. Trailing spaces in a record will be
truncated. If no end of record character is found after receiving eighty characters, the A/S-4
will insert an end of record character and truncate any trailing blanks before transmitting the
record to the SNA host. Transparent data received from the VDU will be passed to the SNA
host with no changes, except when the Precede TRN Ctl Chars with DLE option is selected
and a DLE followed by another character is received. When this occurs the DLE character is
thrown away and the following character’s two most significant bits will be changed to zero’s.
For transparent data to work correctly without the DLE option enabled, both the VDU and
the A/S-4 must be set for 8-data bits with no parity and XON/XOFF throttle turned off.
4. End of File (EOF) character is selected by H-Application Options menu. This single character
command terminates the transmission of the VDU data. This command can also be disabled
(turned off) so that no EOF character is sent, but if disabled all data received may not be sent
to the host.
8.3 Batch Printer Operation
Data received from the SNA host directed to the printer device by the use of the function management
header - 1 (LU Type 1) or by the write control character (WCC) (LU type 3) is handled differently than
card, console or disk data. This printer data is inspected for SNA Character String (SCS) control codes,
space characters and transparent data indication. Most of the SCS codes are single character commands
(e.g. NL, BS, LF) which are converted into their ASCII equivalent (see appendix C), but a few SCS
commands are two or more characters long which are handled as described below:
1. Set Horizontal Format (SHF) command defines the maximum presentation position (MPP),
the left margin (LM), right margin (RM) and up to six horizontal tab stops for a page of print.
This command is used internally by the A/S-4. The printer may receive new operating
conditions depending on printer options selected. Refer to Section 6.12.1, Programmable
Printer Options for details.
2. Set Vertical Format (SVF) command defines the maximum presentation line (MPL), top
margin (TM), bottom margin (BM) and up to six vertical tab stops for a page of print. This
command is used internally by the A/S-4.The printer may receive new operating settings
depending on printer options selected. Refer to Section 6.12.1 for details.
3. Set Line Density (SLD) defines the distance to be moved for a single line (vertical spacing), as
in NL or LF. This command is used internally by the A/S-4, the printer may receive a new
lines per inch (LPI) setting depending on printer selections. See Section 6.12.1 for details.
4. Vertical Channel Select (VCS) selects one of 12 vertical channels to control vertical formatting
of the page. This two character command causes a line feed (LF) to be sent to the printer.