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D-sub
Cannon D-subminiature — IEC 60807-3

D-subminiature, abbreviated D-sub, is a common series of electical connectors, introduced by Cannon in 1952 and often used with computer-related equipment [1]. The D-sub series is often eroneously referred to as Sub-D or D-Type. Following Cannon's numbering scheme, the letter 'D' is used as a prefix for all connectors of this series, whilst the second letter specifies the size.


The prefix is followed by a number that specifies the number of pins. Historically, the 9-pin DE-9 was introduced after the 25-pin DB-25 (and in many cases replaced it, for example with serial ports), and is therefore often wrongly labelled as DB-9, ignoring the fact that 'E' denotes the size of the case shell. The female part (socket) is known as DE-9S and the male part (plug) is DE-9P.


With the original D-series, the pins are spaced 2.76 mm, whilst the rows are 2.84 mm apart, as shown in the drawing above. These parameters in defined in the IEC 60807-3 and DIN 41652 standards. There are also D-sub connectors with larger power conductors or coaxial inserts in place of some of the regular contacts. In such cases this will be denoted with a suffix, e.g.:


Nomenclature
  • D-sub
  • D-subminature
  • DIN 41652
  • IEC 60807-3
  • sub-D 1
  • D-Type 1
  • DB connector 1
  1. The names in red are frequently used but are actually incorrect.

Layout
Below is the layout of several popular configurations, when looking into the (female) socket.

DA-15
Shape
A
Pins
15
Layout
8, 7
Usage
Ethernet (10Base5)
  

DB-25
Shape
B
Pins
25
Layout
13, 12
Usage
Serial (RS-232), modem, parallel printer
SCSI, V.10
  

DC-37
Shape
C
Pins
37
Layout
19, 18
Usage
SCSI, data/address bus
  

DD-50
Shape
D
Pins
50
Layout
17, 16, 17
Usage
SCSI
  

DE-9
Shape
E
Pins
9
Layout
5, 4
Usage
Serial port (RS-232), RS-422, video (RGB),
keyboard, mouse, joystick
  

DE-15
Shape
E
Pins
15
Layout
5, 5, 5
Usage
Video (RGB), VGA, SVGA, XGA
  


Serial port
RS232   DE-9/P
Below is the pinout for the most common wiring today of an asynchronous serial port (RS232). Commonly known as the Serial Port or COM-Port is can be found on older personal computers, laptops and telecom equipment. Adapters are available to convert between USB and RS232. The plug-version (male) is used on Data Terminal Equipment (DTE), such as a computer or terminal.

  1. DCD
    Data Carrier Detect
  2. RXD
    Receive Data
  3. TXD
    Transmit Data
  4. DTR
    Data Terminal Ready
  5. GND
    Ground
  6. DSR
    Data Set Ready
  7. RTS
    Request To Send
  8. CTS
    Clear To Send
  9. RI
    Ring Indicator
    DE-9P male part
The socket version (female) is commonly used on Data Circuit-Terminating Equipment (DCE) and peripherals, such as modems.

RS232   DE-9/S
  1. DCD
    Data Carrier Detect
  2. TXD
    Transmit Data
  3. RXD
    Receive Data
  4. DTR
    Data Terminal Ready
  5. GND
    Ground
  6. DSR
    Data Set Ready
  7. CTS
    Clear To Send
  8. RTS
    Request To Send
  9. RI
    Ring Indicator
    DE-9S female part
RS232 — V.24   DB-25
This is the oldest standard for RS232 on a computer equipment. It is also known as V.24 and as RS232C, RS232D, RTS232E and TIA232F. It provides a full serial port with modem signals for asynchronous serial communication, and (optionally) a second port for synchronous communi­cation. Typical protocols used over synchronous V.24 are HDLC, X.25, SNA and PPP. Below is the pinout for Data Terminal Equipment (DTE) such as computers and terminals.

Note that not all signals are supported by all equipment. In most cases only a subset is implemented. The most important signals are shown in bold.

  1. GND
    Protective ground
  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. DCD
    Data Carrier Detect
  9. -
    test pin
  10. -
    test pin
  11. -
    unused
  12. DCD 2
    Data Carrier Detect (2)
  13. CTS 2
    Clear To Send (2)
  14. TXD 2
    Transmit Data (2)
  15. DCE
    Transmitter Clock
  16. RXD 2
    Receive Data (2)
  17. RXC
    Receiver Clock
  18. -
    unused
  19. RTS 2
    Request To Send (2)
  20. DTR
    Data Terminal Ready
  21. SQD
    Signal Quality Detector
  22. RI
    Ring Indicator
  23. DSRD
    Data Signal Rate Detector
  24. DCE
    Transmitter Clock
  25. -
    unused
    DE-25P male part
By convention, the plug-version (male) is used for a DTE, but there are exceptions. For example: printers and tape punchers/readers are often defined as DTE (using the pin definitions listed above), but are nevertheless equipped with the socket-version (female) of the connector. In that case, a gender-changer or a specially wired crossover (null-modem) cable should be used.

Below is the pinout of the RS232 port for Data Circuit-Terminating Equipment (DCE) and peripherals, such as modems. By convention, the socket-version (plug) is commonly used on DCE. Note however that there are exceptions. Printers and tape reader/punchers have a female connector (socket) but are nevertheless wired as a DTE. In that case, a special cable is needed.

  1. GND
    Protective ground
  2. RXD
    Receive Data
  3. TXD
    Transmit Data
  4. CTS
    Clear To Send
  5. RTS
    Request To Send
  6. DTR
    Data Terminal Ready
  7. GND
    Signal ground
  8. DCD
    Data Carrier Detect
  9. -
    test pin
  10. -
    test pin
  11. -
    unused
  12. DCD 2
    Data Carrier Detect (2)
  13. RTS 2
    Request To Send (2)
  14. RXD 2
    Receive Data (2)
  15. DCE
    Transmitter Clock
  16. TXD 2
    Transmit Data (2)
  17. RXC
    Receiver Clock
  18. -
    unused
  19. CTS 2
    Clear To Send (2)
  20. DSR
    Data Set Ready
  21. SQD
    Signal Quality Detector
  22. RI
    Ring Indicator
  23. DSRD
    Data Signal Rate Detector
  24. DCE
    Transmitter Clock
  25. -
    unused
    DE-25P male part
RS-530 — V.10   DB-25
V.10 is a balanced variant of the RS-232 standard – defined in RS-530 – intended for longer distances. It was used on teleprinter networks, as an alternative to the existing AD04 and ADo8 standards, for example with the TeKaDe FS-200 teleprinter. Below is the pinout when looking into the plug. When a signal is part of a twisted pair, the wire it is paired with is shown in red in square brackets, like this [18]. The name of the return wire is prefixed with a '/'. When unbalanced signals are used, the return wires should be connected to ground (pin 7).

  1. GND
    Chassis [18]
  2. TXD
    Transmitted data (out) [14]
  3. RXD
    Received data (in) [16]
  4. RTS
    Request To Send (out) [19]
  5. CTS
    Clear To Send (in) [13]
  6. DSR
    Data Set Ready (in) [22]
  7. GND
    Signal ground [21]
  8. DCD
    Data Carrier Detect (in) [10]
  9. /RDS
    Return RX element timing (in) [17]
  10. /DCD
    Return DCD (in) [8]
  11. /TDT
    Return TX element timing DTE (out) [24]
  12. /TDS
    Return TX element timing DCE (in) [15]
  13. /CTS
    Return CTS (in) [5]
  14. /TXD
    Return TXD (out) [2]
  15. TDS
    TX element timing (in) [12]
  16. /RXD
    Return RXD (in) [3]
  17. RDS
    RX element timing (in) [9]
  18. LL
    Local Loopback (out) [1]
  19. /RTS
    Return RTS [4]
  20. DTR
    Data Terminal Ready (out) [23]
  21. RL
    Remote Loopback (out) [7]
  22. /DSR
    Return DSR (in) [6]
  23. /DTR
    Return DTR (out) [20]
  24. TDT
    TX element timing (out) [11]
  25. -
    Test Mode (in)
V.21 — X.21   DA-15
V.21 is a standard for serial communication as used with the X.21 interface. It was specified by CCITT in 1976 as a digital signalling interface between the customer's Data Terminal Equipment (DTE) and the carrier's Data Carrier Equipment (DCE). All signals are balanced as with RS-422.

  1. GND
    Shield
  2. TXD A
    Transmit data (A)
  3. CON A
    Control (A)
  4. RXD A
    Receive Data (A)
  5. IND A
    Indication (A)
  6. ST A
    Signal Timing (A)
  7. -
    unused
  8. GND
    Common
  9. TXD B
    Transmit Data (B)
  10. CON B
    Control (B)
  11. RXD B
    Receive Data (B)
  12. IND B
    Indication (B)
  13. ST B
    Signal Timing (B)
  14. -
    unused
  15. -
    unused
    DA-15S female part
RS-422
Below is a regularly used pinout for using RS-422 over a DE-9 connector. Note that Sony equipment uses a different layout (see below).

  1. TXD- 
  2. TXD+ 
  3. RTS- 
  4. RTS+ 
  5. GND  
  6. RXD- 
  7. RXD+ 
  8. CTS- 
  9. CTS+ 
    DE-9P male part
Sony 9-pin protocol — master
Below is the pinout for RS-422 communication as defined by Sony for Master devices. This pinout was widely used in the 1980s and 90s on professional broadcast equipment, and is still used today with harddisc and solid state video recorders. It is being replaced by Ethernet.

  1. Ground (chassis)
  2. RX A
  3. TX B
  4. TX Common
  5. Spare or Ground
  6. RX Common
  7. RX B
  8. TX A
  9. Ground (chassis)
    DE-9P male part
Sony 9-pin protocol – slave
Below is the pinout for RS-422 communication as defined by Sony for Slave devices. This pinout was widely used in the 1980s and 90s on professional broadcast equipment, and is still used today with harddisc and solid state video recorders. It is being replaced by Ethernet.

  1. Ground (chassis)
  2. TX A
  3. RX B
  4. RX Common
  5. Spare or Ground
  6. TX Common
  7. TX B
  8. RX A
  9. Ground (chassis)
    DE-9P male part


Video
VGA, SVGA, XGA
Below is the pinout of the 15-pin DE-15 used on the VGA, SVGA and XGA cards of a Personal Computer (PC) and on the accompanying monitor. The computer had a DE-15S receptacle. The monitor had a fixed cable or a DE-15S receptacle, in which case a 1:1 male/male cable could be used. The ID0-ID3 lines are used for identification of the monitor, but are often omitted.

  1. Red
  2. Green
  3. Blue
  4. ID2
  5. GND
  6. GND Red
  7. GND Green
  8. GND Blue
  9. key (no pin)
  10. GND Sync
  11. ID0
  12. ID1 or SDA
  13. H-Sync or C-Sync
  14. V-Sync
  15. ID3 or SCL
    DE-15S female part
Philips CM8833 RGB analogue   DE-9
  1. GND
  2. GND
  3. Red
  4. Green
  5. Blue
  6. Fast blanking
  7. Composite sync
  8. H sync
  9. V sync
    DE-9S female part
Philips CM8833 RGB TTL   DE-9
  1. GND
  2. GND
  3. Red
  4. Green
  5. Blue
  6. Intensity
  7. unused
  8. H sync
  9. V sync
    DE-9S female part of the computer and/or minitor


Printer
Centronics   DB-25
  1. STR
    Strobe (in/out)
  2. D0
    Data bit 0
  3. D1
    Data bit 1
  4. D2
    Data bit 2
  5. D0
    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
    Acknowledge
  11. BSY
    Busy
  12. PE
    Paper Out
  13. SI
    Select In
  14. AF
    Auto linefeed
  15. ERR
    Error
  16. INIT
    Reset
  17. SO
    Select Out
  18. GND
    Signal ground
  19. GND
    Signal ground
  20. GND
    Signal ground
  21. GND
    Signal ground
  22. GND
    Signal ground
  23. GND
    Signal ground
  24. GND
    Signal ground
  25. GND
    Signal ground
    DE-25S female part



References
  1. Wikipedia, D-subminiature
    Visited April 2021.

  2. Wikipedia, SCSI connector
    Visited April 2021.

  3. Wikipedia, RS-232
    Visited January 2025.

  4. Wikipedia, Serial port
    Visited January 2025.
Further information
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© Crypto Museum. Created: Friday 02 April 2021. Last changed: Tuesday, 14 January 2025 - 11:19 CET.
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