Hardware Reference
In-Depth Information
have front-mounted USB ports, letting you easily attach and remove a USB mouse without the
use of an external hub.
Virtually all mice today interface via USB; however, some USB mice are hybrid devices that also
support the PS/2 interface via an adapter.
Note
Even the fastest “gaming” mice with the highest DPI (dot per inch) ratings use the USB 1.1
compatible “Full Speed” data rate, which is 12Mbps. That is 960 times faster than the
12.5Kbps data rate used by the PS/2 port interface. The higher data rates of USB 2.0 Hi Speed
(480Mbps) and USB 3.0 SuperSpeed (5Gbps) are simply not needed even for the fastest mice.
Hybrid Mice
Hybrid mice are those designed to plug into two types of ports. Circuitry in a hybrid mouse
automatically detects the type of port to which it is connected and configures the mouse automatically.
Serial-PS/2 hybrid mice came with a mini-DIN connector on the end of their cable and an adapter that
converts the mini-DIN to a 9- or 25-pin serial port connector, although the reverse is sometimes true
on early examples of these mice. PS/2-USB hybrid mice usually come with the USB connector on the
end of their cable and include a mini-DIN (PS/2) adapter, as shown in
Figure 15.13
.
Figure 15.13. A typical USB mouse with a PS/2 adapter.
Sometimes, people use adapters to try to connect a USB mouse to a PS/2 mouse port or a PS/2 mouse
to a USB port. If this does not work, it is not the fault of the adapter. Non-hybrid mice are
incompatible with adapters and will only work on the specific interface for which they were
designed.
Scroll Wheels
Late in 1996, Microsoft introduced the IntelliMouse, which differed from standard Microsoft mice by
adding a small gray wheel between the mouse buttons. Although this was not technically the first
