Hardware Reference
In-Depth Information
portaddresses60hand64h.Becausethemotherboardmouseportusesthe8042-typekey-
board controller chip, the port addresses are those of this chip. IRQ12 is an interrupt that
isusuallyfreeonmostsystems,butifyouuseaUSBmouse,youcanprobablydisablethe
mouse port to make IRQ12 available for use by another device.
Hybrid Mice
Hybrid mice are those designed to plug into two types of ports. Although a few low-cost
mice sold at retail are designed to plug into either the serial port or the PS/2 port, most
mice on the retail market today are designed to plug into either the PS/2 port or the USB
port. These combination mice are more flexible than the mice typically bundled with sys-
tems, which are designed to work only with the PS/2 or USB port to which they attach.
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 usually come 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 ex-
amples of these mice. PS/2-USB 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 15.12
.
Figure 15.12
A typical USB mouse with a PS/2 adapter.
Sometimes people use adapters to try to connect a serial mouse to a motherboard mouse
port or a motherboard mouse to a serial port. If this does not work, it is not the fault of
the adapter. If the mouse does not explicitly state that it is both a serial and a PS/2-type
