RS232 pinout and signals. RS232 cables layout
Most visitors need one of these pages: the full 25-pin RS232 pinout (DB-25) with all signals, the DB9 pinout of the PC serial port, or the null modem cable pinout (DB9-DB9) for connecting two computers. The RS232 connector pinouts page compares DB9, DB15, DB25 and RJ45 on one page.
Serial port interface
Serial port interface introduction
RS232 to RS232: connecting two computers or devices
Null modem cable (DB9-DB9): two computers or two DTE devices with 9-pin ports.
Null modem cable (DB25-DB25) for 25-pin ports, and DB9-DB25 for a mixed pair.
Modem (straight) cable: computer to modem or another DCE device.
Serial port pinout and signal
The serial port is an I/O (Input/Output) device. An I/O device is just a way to get data into and out of a computer. There are many types of I/O devices such as serial ports, parallel ports, disk drive controllers, Ethernet boards, universal serial buses, etc. Most PC's have one or two serial ports.
Connectors and signals
RS232 pinout and signals
Serial port pinout and signals
Full DB25 serial (RS232) port pinout and signals
DB9 pinout and signals
DB25 pinout and signals
RS232 RJ45 pinout (EIA-561, Cisco console)
DB15 serial pinout (X.21)
RS232 loopback plug (DB9 and DB25) and how to test a port
Serial printer
Serial port cables and signals
While the normal PC hardware might well run with just Tx, Rx and Ground connected, most driver software will wait forever for one of the handshaking lines to go to the correct level. Depending on the signal state it might sometimes work, other times it might not.
Serial port and
RS232 port cables and signals
Serial and RS232
port monitor cables
Serial data transfer
cable
Serial (RS232) two-wire
modem cable (DB25-DB25)
Serial (RS232) two-wire
modem cable (DB9-DB25)
Serial (RS232) modem
cable (DB25-DB25)
Serial (RS232) modem cable
(DB9-DB25)
Serial (RS232) modem cable
(DB9-DB15)
Null modem cable
(DB25-DB25)
Null modem cable (DB9-DB25)
Null modem cable (DB9-DB9)
Serial printer cable (DB25-DB25)
Serial printer cable (DB9-DB25)