Black Box PROTOCOL CONVERTER A/S-4 - Manual (Page 56)

CHAPTER 8: Batch Operation
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8.2 Transmitting Batch Data to the SNA Host
To send data to the SNA computer, the data from the VDU should look like this:
Device
Selection
Start or End
of Special of
File Control File
1 STX 2 3 Data 4 ETX
1. Start of File (SOF) character is selected by H Application Options menu. This single
character command can be disabled (turned off) so that no SOF character needs to be
received before handling the incoming data from the VDU.
2. a Device selection character indicates which device (card, disk, printer or console) the data
is from, if the data is in transparent form and which Logical Unit (LU) should transmit
the data to the SNA host. This character is not sent to the SNA host. The following is
the Device Selection character with its assigned bits:
Bit 7 6 5 4 3 2 1 0
1 1 Y X X
1 = Outbound LU data
0 = Inbound LU data
1 = Transparent data XX = 00 - Console Data
0 = Normal data 01 - Disk Data
10 - Card Data
Parity bit can be 0 or 1 11 - Printer Data
Y = Do Not Care
Example: Device selection character of “2”(X`32’) would cause the data to transmit to the SNA host as
normal card data by the inbound (VDU) LU.
2.b Special Control (SC) character precedes some types of data mentioned below:
1) SO(X`0E’) character readies the A/S-4 to receive new options following the SO
character. For this to work, the A/S-4 and the VDU must be set for a character length
of 8-data bits with no parity. The contents of this string of options is described later.
The SO (X`0E’) character does not need to be preceded by the Start of File character
or followed by an End of File character.