Serial (RS232) printer. Pinout and signals for the serial printer connector

DB25 pin D-SUB male at the printer DB25 pin D-SUB male (at the printer)

Pin Name Direction Description
1 SHIELD Shield Ground
2 TXD Transmit Data
3 RXD Receive Data
4 n/c - Not connected
5 n/c - Not connected
6 DSR Data Set Ready
7 GND System Ground
8 DCD Data Carrier Detect
9 n/c - Not connected
10 n/c - Not connected
11 ? Reverse Channel
12 n/c - Not connected
13 n/c - Not connected
14 n/c - Not connected
15 n/c - Not connected
16 n/c - Not connected
17 TTY-TXD TTY Receive Data
18 n/c - Not connected
19 n/c - Not connected
20 DTR Data Terminal Ready
21 n/c - Not connected
22 n/c - Not connected
23 ? TTY Receive Data Return
24 ? TTY Transmit Data Return
25 TTY-RXD TTY Receive Data