A serial port is a communication interface between computers and peripherals where information is transmitted bit by bit by sending a single bit at a time (in contrast to the parallel port to send multiple bits at a time).
ultimate serial port is RS-232 using simple wiring from 3 to 25, with wires connecting computers or microcontrollers to all types of peripherals, from printers and modems terminals through mice.
The interface between the RS-232 and the microprocessor generally is done through the integrated 82C50.
The original RS-232 had a D-type connector 25-pin, however most of these pins is used, so joined from IBM PS / 2 connector only smaller 9-pin which is currently used.
In Europe the standard RS-422 of German origin is also a widely used standard in the industrial field.
One shortcoming of the initial serial ports was being slow compared to the parallel port, however, over time, the emergence of a multitude of serial ports with high speed which makes them very interesting as they have the advantage of a minor wiring and solve the problem the speed with increased screening, are cheaper because they use twisted pair technology, which is why the RS-232 and even many parallel ports are being replaced by new serial ports such as USB, Firewire or Serial ATA. The serial ports used to communicate to the computer with printer, mouse or modem, but specifically, the USB port is used for all types of peripherals, from mice, external hard drives, up bluetooth connection. Ports SATA (Serial ATA) have the same function as IDE (connects them, the floppy drive, hard drive, DVD / CD recorder and DVD's) but have more speed SATA. A port network can be serial or parallel port.
