Mini PCI
Mini PCI (peripheral component interconnect) is a standard used by leading notebook manufacturers that measures 2.75-inches x 1.81-inches x 0.22-inches. This technology could allow manufacturers to lower their prices, as the motherboards would be simpler to design.
Type I
Identical to type II, except it requires extra cables for connectors like the RJ-11 and RJ-45. However, offers more flexibility to where it can be placed in the computer.
Type II
Used when size is not important. Type II can integrate the RJ-11 and RJ-45 connectors and did away with extra cables.
Type III
SO-DIMM (small outline dual in-line memory module) style connector that can be installed with a mere 5 mm overall height above the system board. Cabling to the I/O connectors also allow type III cards to be placed anywhere in the system.