All about DB25 connector: pins, male, female

All about DB25 connector: pins, male, female

The DB25 (originally DE-25) connector is an analog 25-pin plug of the D-Subminiature connector family (D-Sub or Sub-D). The DB25 connector is mainly used for serial connections, allowing for asynchronous data transmission as provided by standard RS-232 (RS-232C). It is also used for parallel port connections and was used to connect printers, that's why it's also known as a printer port (LPT). DB25 serial ports on computers have male connectors, while parallel port connectors are DB25 female.

How do male and female connectors look like?

DB25 connector

What are pins for serial connection?

Pin number Name  
2 TXD - Transmit Data  
3 RXD - Receive Data  
4 RTS - Request To Send  
5 CTS - Clear To Send  
6 DSR - Data Set Ready  
7 GND - Signal Ground  
8 CD - Carrier Detect  
20 DTR - Data Terminal Ready  
22 RI - Ring Indicator  

What are pins for parallel connection?

Pin number Name  
1 _STR - Strobe  
2 D0 - Data bit 0  
3 D1 - Data bit 1  
4 D2 - Data bit 2  
5 D3 - Data bit 3  
6 D4 - Data bit 4  
7 D5 - Data bit 5  
8 D6 - Data bit 6  
9 D7 - Data bit 7  
10 ACK - Acknowledgement  
11 Busy  
12 Paper Out  
13 Select  
14 Auto feed  
15 Error  
16 Reset  
17 Select Input  
18 Ground  
19 Ground  
20 Ground  
21 Ground  
22 Ground  
23 Ground  
24 Ground  
25 Ground