IBM 2265 Manual page 38

I/O Channel Sequences
and Responses
SOH }
2845 Address Addressing
2265 Address Sequence
Erase/vVrite Command (Hex
=
EO) -
I
,
I
I
I
I
I
.1
2845' Sequences
and Responses
I
I
No Response ACK
STX*
Text
ETX
LRC
I
SOH EOT
I
I
I
I
I
I ,.,
I
I
No Response ACK
NAK
t
STX*
Etc.
SOH
EOT
*
No repeat erase is performed without repeating SOH sequenc.e.
tSee "Error Recovery Procedures" for further I/O channel responses.
Figure 11. Erase/Write Addressed DS, Sequence/Response Diagram
channel that the screen of the selected 2265 is erased and
that the cursor is in the first character position. The I/O
channel response to ACK may be an EOT or SOH (either
of which terminates the operation; see Programming Note,
or it may be the transmission of a message beginning with
STX. The sequences and responses that occur during the
write portion of the operation are the same as those de-
scribed in the Write Addressed DS operation.
An erase function is only performed immediately fol-
lowing the addressing sequence containing the Erase/Write
Addressed DS command (SOH, 2845 Display Control
Address, etc.). Therefore, subsequent erasures requiTe
reinitiating the addressing sequence.
38
PROGRAMMING NOTE: The erase/write addressing seqllence not
followed by a message from the I/O channel is used to erase a par-
ticular 2265 Display Station screen.
Write Printer (Figure 12)
The Write Printer command is used to select a 1053 Printer
when data is to be transferred from the I/O channel and
printed on hard copy. Following the addressing sequence,
an ACK response from the 2845 represents a positive ac-
knowledgment that the selected Printer is ready and not
busy. "Ready" indicates that power is turned on in the
Printer and that the Printer is properly loaded with paper.
"Not busy" indicates that the printer buffer of the 2845