Working mode of parallel port
1. Spp is called standard parallel port. It is the first parallel port working mode. Almost all peripherals using parallel port support this mode.
2. EPP, called enhanced parallel port, is a new working mode developed on the basis of spp. It is also the most widely used parallel port mode of operation. Currently, most printers and scanners on the market support EPP Mode.
3. ECP is an extended capability port. At present, it is a relatively advanced parallel port mode, but there are more compatibility problems. Do not select ECP mode unless the peripheral device supports it.
The difference between serial port and parallel port
A serial port is described as a channel, while a parallel port means that eight channels can simultaneously transmit 8 bits (one byte) of data.
However, due to the interference between 8-bit channels, it is not parallel fast. Speed is limited during transmission. In addition, when a transmission error occurs, the 8-bit data must be retransmitted at the same time. There is no interference in the serial port, only a bit is retransmitted after a transmission error. Therefore, it is faster than parallel processing. Serial hard drives are valued in this way.