Radio Shack TRS-80 Model III - Page 100

TRS-80
MODEL
RS-232-C Pin Location
Looking from
the
outside at
the
RS-232-Cjack
on
the
Model III Computer:
c
j
^7777777777???
^
Parallel Printer Interface
Signal
Function
Pin#
STROBE*
1 .5
(jlS pulse
to
clock the data
from
processor to
printer
1
DATAO Bit (Isb) of output data byte
3
DATA1 Bit 1 of output data byte
5
DATA 2 Bit 2 of output data byte
7
DATA 3 Bit 3 of output data byte 9
DATA 4 Bit 4 of output data byte
11
DATA 5 Bit 5 of output data byte
13
DATA
6
Bit
6
of output data byte
15
DATA
7 Bit 7
(msb)
of output data byte
17
BUSY Input
to
Computer from Printer, high
indicates busy
21
PAPER Input
to
Computer
from Printer, high 23
EMPTY
Indicates no
paper
—
if Printer doesn't
provide this,
signal is
forced low
SELECT Input to
Computer from Printer, high
indicates device
selected
25
FAULT* Input
to
Computer from Printer, low
indicates fault (paper empty, light
detect,
deselect, etc.)
28
GROUND Common signal ground
2,4,6,8,10
12,14,16,18,
20,22,24,27,
31 ,33,34
NC
Not connected
or not used 26,29,30,32
These
signals
are
active-low.
90