USE of Carriage Return a 2770/2780 Mode

PROTOCOL CONVERTER A/S-2G

ASCII CHARACTERS NOT TRANSLATED TO EBCDIC

CR (Carriage Return) when SW3, Switch #3 is ON, LF (Line Feed), Control characters are not passed.

Character	Hex	Character	Hex
NUL	00	ACK	06
SOH	01	DLE	10
STX	02	NAK	15
ETX	03	SYN	16
EOT	04	ETB	17
ENQ	05	US	1F

Table 4-2. ASCII characters not translated to EBCDIC.

In 3741 protocol, each block contains only one record. If SW3, Switch #5 is OFF, the A/S-2G will fill the block with spaces until it reaches 128 characters . If SW3, Switch #5 is ON, the block will end immediately after CR.

NOTE:

•If SW3, Switch #3 is OFF, then one character of the total count must be allotted to the CR. The CR will be translated into EBCDIC as a NL (New Line). Thus, if block size is specified as 80 characters, 79 characters plus the CR would make a full 80 character record. Entering 80-characters and a CR would cause 2 records to be sent: one with the 80 characters; the second with the NL character and, if SW3, Switch #5 is OFF, 79 spaces.

•When SW3, Switch #3 is ON, the A/S-2G will delete CR from the character count and send no representation of the CR with the EBCDIC data.

4.1.5USE OF CARRIAGE RETURN (A) 2770/2780 MODE

Data from the asynchronous device is buffered (stored in RAM) until a CR (ASCII 0D Hex) is entered. If the A/S-2G receives asynchronous characters up to the selected block size without receiving a CR character, the A/S-2G will add an IUS character and a 2-byte CRC sequence to the block.

When the A/S-2G receives a CR, the A/S-2G sends any buffered data to the synchronous device with an ETB (EBCDIC Hex 26).

The last block of asynchronous data must end with a “Control D” (ASCII Hex 04). The A/S-2G will send the block, adding with an ETX (EBCDIC Hex 03). After receiving a positive acknowledgement, the A/S-2G sends an EOT.

(B) 3741/3780 MODE

Data from the asynchronous device is buffered until a CR (ASCII 0D Hex) is entered. When the A/S-2G receives a CR, the A/S-2G inserts an IRS (EBCDIC 1E Hex). Data will continue to accumulate until the selected block size is exceeded. At this point, the A/S-2G sends the full block of data.

4.1.6 FLOW CONTROL

The input buffer (RAM) is capable of storing up to 1720 characters. The asynchronous device can continuously send data to the A/S-2G if RAM is available and the character string contains a CR code before the buffer fills. (However, the maximum block size that is acceptable to the synchronous device must be considered.)