Black Box A/S-4 manual Transmitting Batch Data to the SNA Host, Stx, Etx

CHAPTER 8: Batch Operation

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.

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