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APPLICATIONS
I~
INTRODUCTION
if the data was OK and a NAK
This appendix contains sample applications using the
terminal's unique features. They can be used as a guide in
developing your own applications.
S
S
S
y
Y
y
N
N
N
S
N
Y
A
N
K
MULTIPOINT EXAMPLE
We wish to send the printer status query escape sequence
to terminal DA. In multipoint, this requires selecting that
terminal first. Send the select sequence
Suppose we have a group of terminals set up in a syn-
chronous multipoint configuration. We wish to determine
status of the left cartridge of the terminal with group ID D
and device ID A.
S
S S E
P
S
S
S
S
y
Y Y
0
A
Y
Y
Y
Y
N
N N
T
D N N
N
N
E
P
N
A
d d
A A
Q D
-- --
Lower Upper
Case
Case
if not. In the latter case retransmit the escape sequence
above; either a parity error occurred or the BCC is wrong.
Check that the proper parity is selected on the keyboard
switch and the proper BCC is strapped on the data comm
card.
To receive the printer status, poll terminal DA: send
S
S
S
E
P
S
S
S
S
E
P
Y
Y
Y
0
A
Y
Y
Y
Y
N
A
N
N
N
T
D
N
N
N
N DD AA
Q
D
After turnaround, you may receive from the terminal
S
S
S S E
Y
Y
Y
Y
0
N
N
N
N
T
Turn around the line again and give the terminal the
cartridge status request embedded in the appropriate pro-
tocol characters:
Note the sync characters present before and after the EOT
PAD (there must be at least
3
in both places). Turn the
line around to receive (multipoint is half duplex) and the
terminal will send an ACKO to indicate it is ready to
receive:
S
S
S
S
E
E
B
P
Y
Y
y
T
S
&
p
1
1\
T
C
A
N
N
N
X
C
I
8L
X
C
D
~
t
I
I/O Control
1 or 2 chars
escape
TUS
you have
sequence
LEFT
calculated
Cart-
depending
ridge
on type of
BCC chosen
After flipping to receive mode, the program will get:
1
S
S
D
Y
Y
L
N N E
S
S
Y
Y
N
N
S
S
S
S
S
E
E
B
Y
Y
Y
Y
T
S
C
L
G
T
C
N
N
N
N
X
DA C/P
021
R
F
S
X
C
Tennin.]/ I
\
' "
Status
Cartridge
Block
ID
Header
Status
Terminator
Bytes
for Multi-
point
You should check the BCC the terminal sends to assure
the integrity of the data.
If it checks and no parity errors were detected, send the
terminal an ACKI after you turn the line around:
This means the terminal is not yet ready to send status.
Poll again until you receive it:
o
S
D
Y
L
N
E
S
S
S
Y
Y
Y
N
N
N
The terminal returns an ACKI after the next turnaround
S
S
S S E
Y
Y
Y
Y
0
N
N
N
N
T
S
S
S
S
D
Y
Y
Y
Y
L
N
N
N N E
1
from the terminal indicating it has no more data to send
for the moment. Now the program may examine the status
byte to glean whatever information it desires from them.
A-I
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