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).

Parallel cable is the cable for computers defined by the IEEE 1284 standard for connecting peripherals via the parallel port. It is often used for connecting printers compatible PC computers. It is considered an outdated connection and has been replaced by USB. - IEEE 1284 Type A: 25-pin DB-25 IEEE 1284 - IEEE 1284 Type B: 36 Drivers, Champ type Centerline Connector 0.085 insurance (Centronics). - IEEE 1284 Type C: 36 conductors, connector type mini Champ de Centerline 0.050 with secure clip (mini Centronics).