IEEE 1284
IEEE Standard 1284 describes a parallel printer interface with its bidirectional extensions, the Enhanced Parallel Port( EPP) and the Extended Capability Port( ECP). Unlike the Standard Parallel Port( SPP), IEEE 1284 supports simultaneous bidirectional operation between a computer and printer or other peripheral device. Data is transferred in parallel using eight bits of data.
The 1284 standard, which succeeded the Centronics interface, specifies connectorpinouts, protocols, and data rates up to 1.5 Mbps. The cables described in IEEE 1284 are low- capacity cables that can be used to connect printers up to 10 m apart. Unlike the Centronics interface, which transfers data from the computer to the printer, the 1284 interface supports bidirectional data transfer between the computer, printer, CD drives, DVD drives, and tape drives.
Data transfer can be performed in several modes: Unidirectional between computer and peripheral, Unidirectional in opposite direction and Bidirectional.