Serial PORT and parallel port are used for transferring data in/out of the computer. In serial port transmission only 1 bit is transmitted at a time. Most serial ports on personal COMPUTERS conform to the RS-232C or RS-422 STANDARDS. A parallel interface for connecting an external device such as a printer. On PCs, the parallel port uses a 25-pin connector (type DB-25) and is used to CONNECT printers, computers and other devices that NEED relatively high bandwidth. It uses parallel transmission of data.

Serial port and parallel port are used for transferring data in/out of the computer. In serial port transmission only 1 bit is transmitted at a time. Most serial ports on personal computers conform to the RS-232C or RS-422 standards. A parallel interface for connecting an external device such as a printer. On PCs, the parallel port uses a 25-pin connector (type DB-25) and is used to connect printers, computers and other devices that need relatively high bandwidth. It uses parallel transmission of data.