Black Box PROTOCOL CONVERTER A/S-4 - Manual (Page 54)

CHAPTER 8: Batch Operation
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8.1 Receiving Batch Data from the SNA host
When SNA data is received from the host by the A/S-4, the data is sent to the VDU as follows:
Start Special End of
VDU CMD Device On of File Control File VDU
1 2 3 STX 4 5 Data 6 ETX 1
CMD Device Off
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1. VDU CMD or CRT lead in character is selected by C-VDU commands menu. This single or
dual character command is not sent to the VDU if the Device ON command is selected for a
control character (X`1F’ or less) or disabled by being set to a space.
2. Device (Printer, Card, Disk) On is selected by C-VDU commands menu. This single or dual
character command directs the received SNA data to the correct device; printer, card or disk.
This command can also be disabled (turned off) by setting it to a space so that no Device On
is sent. If the command is set to a printable character (X`21’ or greater) the VDU CMD will
precede the Device On command.
NOTE
Console data is not preceded by a VDU CMD or a Device On character.
3. Start of File (SOF) character is selected by H- Application Options menu. This single
character command can be disabled (turned off) so that no Start of File character is sent.
4. Special Control (SC) characters precede some types of data mentioned below:
a. SOH ($01) character indicates that a Function Management Header-2 follows. The FMH-2
data is sent to the VDU without converting the SNA EBCDIC data to ASCII (transparent
mode) inserting DLE’s before ASCII control characters if needed. The VDU CMD and
device selection are sent along with this message if selected.