Printronix L5520 - Manual (Page 218)

Appendix C Host I/O Interfaces
218
RS-232 Serial Interface Connector Pin Assignments
The printer provides a 25-pin DB-25S connector on the right, rear
side panel for connection of a serial interface cable. This connector
is also used for the RS-422 serial interface. Selection of the desired
interface is determined by the position of the RS-232/422 switch
located on the right, rear side panel of the printer.
Table 8 lists the pin assignments of the RS-232 interface
connector.
Table 8
Pin Signal Direction
1 Chassis Ground Not applicable
2 Transmit Data (TxD) From printer
3 Receive Data (RxD) To printer
4 Request To Send (RTS) From printer
5 Clear To Send (CTS) To printer
6 Data Set Ready (DSR) To printer
7 Signal Ground Not applicable
8 Carrier Detect (CD) To printer
11, 14 Reverse Channel (RC) From printer
20 Data Terminal Ready (DTR) From printer