Contact Info

Crumbtrail » Serial Port Component » Tutorials » RS232

RS232 Serial Port Connector Pin Layout

RS-232 is a serial communications standard that provides asynchronous and synchronous communication capabilities, such as hardware flow control, software flow control, and parity check. It has been widely used for decades. Almost all gears, instruments with digital control interface, and communications devices are equipped with the RS-232 interface. The typical transmission speed of an RS-232 connection is 9600 bps over a maximum distance of 15 meters.

The following document describes the functions of the pins on the RS232 9 and 25 pin Sub-D connectors used in serial communications. The pins in the images are as viewed from the pin side (not the solder or printed circuit board side). The male sockets are used on the DTE (Data Terminal Equipment ) or PC side. The female sockets are on the DCE (Data Communication Equipment ) or Modem Side.

Using the ActiveXperts Serial Port Component you can send and receive data and control the RS232 port.

RS232 9 Pin connector (DB-9)

1 DCD Data Carrier Detect
2 RD Received Data
3 TD Transmitted Data
4 DTR Data Terminal Ready
5 GND Signal Ground
6 DSR Data Set Ready
7 RTS Request To Send
8 CTS Clear To Send
9 RI Ring Indicator

RS232 25 Pin connector (DB-25)

1 PG Protective Ground
2 TD Transmitted Data
3 RD Received Data
4 RTS Request To Send
5 CTS Clear To Send
6 DSR Data Set Ready
7 SG Signal Ground
8 CD Carrier Detect
9 - Reserved
10 - Reserved
11 - Unassigned
12 SCD Secondary Carrier Detect
13 SCTS Secondary Clear To Send
14 STD Secondary Transmit Data
15 TC Transmitter Clock
16 SRD Secondary Received Data
17 RC Receiver Clock
18 - Unassigned
19 SRTS Secondary Request To Send
20 DTR Data Terminal Ready
21 SO Signal Quality Detector
22 RI Ring Indicator
23 DRS Data Rate Selector
24 DRS Data Rate Selector
25 - Unassigned