Bus mouse

A bus mouse is a variety of PC computer mouse which is attached to the computer using a specialized interface (originally, the Microsoft InPort interface developed for Microsoft's original mouse product).

Microsoft InPort™ bus mouse, showing the 9-pin round connector

Label on the bottom of a Microsoft InPort™ bus mouse, showing the FCC ID "C3K7PN9937"

Bus mouse

A Microsoft InPort bus mouse adapter, in the form of an 8-bit ISA (XT-bus) card.
Type	Computer mouse input port
Production history
Designer	Microsoft
Designed	late 1980s
Produced	1980s to 2000
Superseded by	PS/2 port, USB (2000 (2000))
General specifications
External	Yes
Cable	9 wires plus shield
Pins	9
Connector	Mini-DIN-9
Data
Data signal	30–200 Hz (interrupt mode) with 3 button state signals and quadrature signals for mouse movement
Pin out
Female port pin layout from the front
Pin 1	SW2	Mouse button 2
Pin 2	SW3	Mouse button 3
Pin 3	GND	Ground
Pin 4	XB	X position
Pin 5	YA	Y position
Pin 6	YB	Y position
Pin 7	SW1	Mouse button 1
Pin 8	Vcc	+5 V Power
Pin 9	XA	X position
XA/XB and YA/YB indicate movement and direction based on quadrature phase.

In the late 1980s, mice were not integrated with IBM-compatible personal computers, and the specialized bus interface (implemented via an ISA add-in card) was one of two popular ways to connect a mouse. (Serial interfaces, common on engineering workstations, were the other method.) When the IBM PS/2 was introduced, it included a motherboard mouse interface which was integrated with the keyboard controller (still called the PS/2 mouse interface long after the PS/2 brand was withdrawn); this fairly quickly drove the bus mouse design out of the marketplace.

The bus mouse lived on in the NEC PC-98 family of personal computers in Japan.