CARETAKER PLUS INSTALLATION AND OPERATIONS MANUAL
31
Serial Models DB25 Female
Pin
Signal Name
Acronym
I/O
Description
2
Transmit data
TXD
Output
Serial data from port
3
Receive data
RXD
Input
Serial data to port
4
Request to send
RTS
Output
Always high
6
Data set ready
DSR
Input
Low inhibits transmit data
7
Signal ground
GND
Common
20
Terminal ready
DTR
output
Pin 20 is the hardware flow control output. Pin 6 is the hardware flow control input.
Pin 6 has an internal pull-up to set it high when no signal is connected.
Parallel Models Centronics 36 Female
DB25 Female
C36F
Pin
DB25
Pin
Signal Name
Port 0
Port 1-8
Description
1
1
STROBE
output
input
Data transfer when pulsed low
2
2
DATA 0
output
input
Data LSB
3
3
DATA 1
output
input
4
4
DATA 2
output
input
5
5
DATA 3
output
input
6
6
DATA 4
output
input
7
7
DATA 5
output
input
8
8
DATA 6
output
input
9
9
DATA 7
output
input
Data MSB
10
10
ACK
input
output
Pulsed low for next transfer
11
11
BUSY
input
output
If high inhibits data flow
12
12
PAPER END
input
output
Input unused, low when output
13
13
SELECT OUT
input
output
Input unused, high when output
14
14
AUTOFEED
output
input
Input unused, output high
16
GROUND
--------
--------
Wired common all ports
19-30
18-25
GROUND
--------
--------
Wired common all ports
31
16
INITIAL
output
Input
Must be high to receive data
32
15
ERROR
Input
output
Input unused, high when output
33
-
GROUND
--------
--------
Wired common all ports
36
17
SELECT IN
output
input
Must be low to receive data