Service manual
REV.-A
(Continued)
Signal
Return
Signal
Dir.
Pin No.
Pin No.
Description
Name
10
28
ACKNLG
out
Approx.12
us
pulse. LOW indicates that data has been
received and that the printer is ready to accept more data.
11
29
BUSY
out
A HIGH signal indicates that the printer cannot receive more
data. The signal becomes HIGH in the following cases:
1. During data entry
2. During input buffer full
3. During printer error status
12
30
PE
out
A HIGH signal indicates that the printer is out of paper.
13
—
—
—
Pulled up to +5V through a 3.3 K-ohm resistor.
14
—
AUTO FEED
In
When this signal is LOW, paper is automatically fed one line
upon receipt of a CR code.
XT
(The signal level can be set LOW by default.)
15
—
NC
—
Not used.
16
—
Ov
—
Logic GND level.
17
—
CHASSIS
—
Printer chassis GND.
GND
In the printer, the chassis
GND and the logic GND are
short-
circuited.
18
—
NC
—
Not used.
9 to 30 —
GND
—
TWISTED-PAIR RETURN signal
GND level.
31
—
INIT
In
When the level of this signal becomes LOW, the printer
controller is reset to its initial state and the print buffer is
cleared. This signal is normally atthe HIGH level, and its pulse
width must be more than 50
ps
at the receiving terminal.
32
—
ERROR
out
The level of this signal becomes LOW when the printer is
in —
1. Paper-out status
2. Error status
33
—
GND
—
TWISTED-PAIR RETURN signal GND level.
34
—
NC
—
Not used.
35
—
— —
Pulled up to
+5V
through a 3.3 K-ohm resistor.
36 —
SLCT IN
In
The data between
DC3
and DCI is invalid when this signal
is HIGH.
(The level of this signal is factory set to LOW.)
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Notes: 1 ) Direction of signal flow is as viewed from the printer.
2) Return means TWISTED PAIR RETURN and is to be connected at signal ground level.
3) Be sure to use a twisted-pair cable for each signal and always complete connection on the return
side. To prevent noise effectively, these cables should be shielded and connected to the chassis
of the host computer and the printer, respectively.
4) All interface conditions are based on
ITL
level. Both the rise and
fall
times of each signal must be
less than 0.2
VS.
5) Data transfer must not be carried out by ignoring the
ACKNLG
or BUSY signal.
(Data transfer to this printer can be carried out only after confirming the
ACKNLG
signal or when .
the level of the BUSY signal is LOW.)
.
:_
.,.
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