HP 262SA - Page 138

Data Communications
ASYNCHRONOUS
Group Poll Characters
I \
Er PAD- A A II II ~ PAD
SYNCHRONOUS
·Optional, but if present, should be FF (hex).
I
ET PAD AA""EaPAD
(Group POLL, group A)
...
t
EOT
I
(Terminals of group A have no data to transmit.)
ET PAD
BB''''Ea
PAD
(Group S terminals have no more data to transmit.)
(Terminal group B device; ETB indicates
more text blocks coming from terminal.)
(Terminal group
B, device G)
(ETX indicates last text block from terminal.)
,
EOT
I
,
STX Text ETX (BCC) PAD
I
,
STX S G Text ETX (SCC) PAD
I
,
ACK1
I
,
ACKO
I
,
ACK1
I
(Group POLL, group B) ,
STX B A Text ETB (BCC) PAD
I
Figure 7-12. Group Poll Sequences
7-26