Mother-board side 9-Pin D Jack connector

Serial PC Mouse PinOut

Computer Mouse Interface Bus

The serial mouse port is not in common usage.
The Mouse port found on most Personal Computers uses a 6-pin mini DIN connector and has the pin out shown the PC Mouse pinout page.
All thought not as common as the PS/2 Mouse interface, a mouse may also be found with a serial interface.
This page provides the pinout for a serial mouse, or a mouse that uses the serial port via a 9-pin D connector.
The mouse used a female plug connector, while the board-side connector used a male jack connector.
Most personal computers stopped using the serial mouse around the year 2000, in favor of a mini-DIN.
For a description of the electrical interface, refer to the RS232 page.

Many new Motherboards just use the USB port as the mouse interface. The Mouse interface runs using standard TTL signaling levels.
The standard cable length is around 4 feet, 6 foot and 10 foot extension cables are also common for the PS/2 mouse interface.
For additional data on the DB9, refer to Dsub 9 Mechanical Dimensions.

9-Pin Serial D-Connector pinout, DB9
D-Sub 9-Pin Connector

Serial Mouse Pin Out
Pin No. Signal name Description
1 NC No Connect
2 RX Receive
3 TX Transmit
4 DTR Data Terminal Ready
5 GND Ground
6 NC No Connection
7 RTS Receive Transmit
8 NC No Connection
9 NC No Connection

Additional PC Mouse Pinout

The MAC used a 4-pin ADB interface for the Mouse interface, now replaced by USB.
The Sun computer used a 8-pin mini-Din for the Mouse interface, also replaced by USB Sun Mouse Pinout.
The personal computer uses a 5-pin mini DIN for the Keyboard interface.
Circular Mini-DIN Pin Locations

Editor note; it's been a number of years since I've had or seen a 9-pin mouse port on back of a PC.
In fact I pitched those 9-pin cable mouse devices years ago, but the pin-out is still good.
Which brings me to the standard statement that this 9-pin D serial interface is obsolete and shouldn't be used in new designs.

PC Mouse Manufacturers

Computer Mouse Manufacturers
KVM Manufacturers [Keyboard - Video - Mouse Switch]

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Modified 12/19/11
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