The SFF connectors are distinguished by their smaller size, they are ideal for saving space. The SFF connectors also increase port density cards, switches etc ..

A Peripheral Component Interconnect (PCI, "Peripheral Component Interconnect") is a bus (picture 2) computer standard for connecting peripheral devices directly to your motherboard. Dimensions of the cards - PCI (standard) 107 mm x 312 mm (picture 1) - PCI Low Profile Height: 36.07 mm x 64.41 mm Depth: 119.91 mm to 167.64 mm - Mini PCI Mini PCI cards have a Maximum consumption2W.

RS-232 (Recommended Standard 232, also known as EIA/TIA RS-232C) is an interface that designates a standard for the exchange of a series of binary data between a DTE (Data Terminal Equipment) and DCE (Data Communication Equipment , Data Communication Equipment), although there are others in which the RS-232 interface is also used. An equivalent definition published by the ITU is called V.24. The RS-232 is a connectorDB-25 type (25-pin), although it is normal to find the version of 9-pin (DE-9, or popularly also called DB-9), cheaper and even extended to certain types of peripherals (such as serial mouse PC).