Dell Precision 420 User Manual page 70

Port designations are used, for example, in software installation procedures that include a step in which you identify the port to which your printer is
attached, thus telling your software where to send its output. (An incorrect designation prevents the printer from printing or causes scrambled print.)
Serial Port Connectors
If you reconfigure your hardware, you may need pin number and signal information for the serial port connectors. Figure 4 illustrates the pin
numbers for the serial port connectors, and Table 3 lists and defines the pin assignments and interface signals for the serial port connectors.
Figure 4. Pin Numbers for the Serial Port Connectors
Table 3. Pin Assignments and Interface Signals for the Serial Port Connectors
Pin Signal
1 DCD
2 SIN
3 SOUT
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
Shell N/A
Parallel Port Connector
If you reconfigure your hardware, you may need pin number and signal information for the parallel port connector. Figure 5 illustrates the pin
numbers for the parallel port connector, and Table 4 lists and defines the pin assignments and interface signals for the parallel port connector.
Figure 5. Pin Numbers for the Parallel Port Connector
Table 4. Pin Assignments and Interface Signals for the Parallel Port Connector
Pin Signal
1 STB#
2 PD0
3 PD1
4 PD2
5 PD3
6 PD4
7 PD5
8 PD6
9 PD7
10 ACK#
I/O Definition
I Data carrier detect
I Serial input
O Serial output
O Data terminal ready
N/A Signal ground
I Data set ready
O Request to send
I Clear to send
I Ring indicator
N/A Chassis ground
I/O Definition
I/O Strobe
I/O Printer data bit 0
I/O Printer data bit 1
I/O Printer data bit 2
I/O Printer data bit 3
I/O Printer data bit 4
I/O Printer data bit 5
I/O Printer data bit 6
I/O Printer data bit 7
I Acknowledge