DB25 connector

The DB25 (originally DE-25) connector is an analog 25-pin plug of the D-Subminiature connector family (D-Sub or Sub-D). As with the DB9 connector, the DB25 connector is mainly used for serial connections, allowing for the asynchronous transmission of data as provided by standard RS-232 (RS-232C). It is also used for parallel port connections, and was originally used to connect printers, and as a result is sometimes known as a printer port (LPT). To avoid confusion, DB25 serial ports on computers generally have male connectors, while parallel port connectors are DB25 female plugs. DB25 connector

Pins (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

Pins (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
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