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).

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.

ExpressCard is a hardware standard replacing the PCMCIA/PC Card/CardBus cards, both developed by the Personal Computer Memory Card International Association. The host device supports PCI-Express and USB 2.0 connectivity in the ExpressCard slot, and each card uses the mode of connectivity the designer considers more appropriate for the task. The cards can connect to the computer on without RESETiarlo (support Hot swap or hot plug). It is an open standard of the ITU-T and its definition can be obtained from the official website of ExpressCard. You can connect to this bus, different types of peripherals such as Wi-Fi cards, Bluetooth, TV cards, FireWire, etc.

The RS232 connector is a connector type 9-pin connector is popularly called Series. It is a connector that was once widely used by various components of the PC, such as a mouse, keyboard ... but over time it has fallen into disuse and replaced by the USB connector trying to emulate the latest version number. It is currently used by robots, elevators, POS and industrial machinery.