Parallel interface, a parallel transmission means to transmit data interface standard. From the most simple a parallel data register or a special interface integrated circuit chip such as the 8255, 6820, has been to more complex SCSI or IDE parallel interface, with ten species. A parallel interface interface characteristics can be described from two aspects: 1 transmitted in parallel data path width, also known as interface transmission bits; 2 is used to coordinate the parallel data transmission additional interface control line or interactive signal characteristics. Data width can be from 1 to 128 or more wide, the most commonly used is the 8 one, through the interface a transmitting 8 data bits. In the field of computer, the most commonly used parallel interface is usually said the LPT interface.

Main characteristics

Parallel interface refers to the data you transfer, which is characterized by fast transmission speed, but when the transmission distance, median and long lines of communication, leading to complex and cost improve.

The difference between serial and parallel ports

Serial describe is: a driveway, and parallel port is 8 lanes in the same time can transmit 8 bits ( one byte) data.

But not parallel fast. Due to the mutual interference between the 8 channels, transmission speed limited. But when the transmission error, at the same time to pass a 8 bit data. While the serial without interference, transmission error retransmission of a can, so than the parallel fast. Serial hard disk is valued by people.

Classification

In the IEEE1284 standard defines a multiplicity of parallel interface mode, commonly used has the following three kinds:

SPP ( Standara Parallel Port ) standard parallel interface

EPP ( Enhanced Parallel Port ) enhanced parallel port

ECP ( Extended Capabilities Port ) extensions parallel interface

These models because of the hardware and programming mode, transmission speed can be increased from 50K to 2MB Bits / S / s range. Generally used to transfer data from a host to a printer, plotter or other digital instrument interface, is called a Centronics 36 foot spring type interface ( usually on the host is a 25 pin type D interface, printer is a 36 pin Centronics interface ).