Parallel Ports

    A bi-directional interface for connecting an external device such as a printer, scanner, or tape drives. Most personal computers have both a parallel port and at least one serial port. On PCs, the printer 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 is often called a Centronics interface after the company that designed the original standard for parallel communication between a computer and printer. (The modern printer interface is based on a design by Epson.)
    A newer type of ports, which supports the same connectors as the Centronics interface, is the EPP (Enhanced Parallel Port) or ECP (Extended Capabilities Port). Both of these printer ports support bi-directional communication and transfer rates ten times as fast as the Centronics port lpt1.
    Macintoshes have a SCSI ports, which is bi-directional, but more flexible.

BPP - Bidirectional Printer Ports. Speed up to 340 KB/sec (slow).
SPP - Standard Printer Ports. Speed up to 340KB/sec (slow).
Centronics interface. Speed up to 340 KB/sec (slow)
A standard interface for connecting printers and other parallel devices. Although Centronics Corporation designed the original standard, the Centronics interface used by modern computers was designed by Epson Corporation. For PCs, almost all parallel ports conform to the Centronics standard. Two new printer port standards that are backward compatible with Centronics, but offer faster transmission rates, are ECP (Extend Capabilities Port) and EPP (Enhanced Parallel Port).
ECP - Enhanced Capabilities Ports. Support speed up to 2MB/sec.
A parallel-ports standard for PCs that supports bi-directional communication between the PC and attached devices (such as a printer). ECP is about 10 times faster than the older Centronics standard.
EPP - Enhanced Parallel Port. Support speed up to 2MB/sec.
A parallel ports standard for PCs that supports bi-directional communication between the PC and attached non-printer devices. EPP is about 10 times faster than the older Centronics standard.

It is best to leave the card's default setting to ECP/EPP, you will get the high through put of up to 2MB/sec regardless of which printer devices you are connecting to the port.

Standard Assignments For Parallel Ports On The IBM PC
PORT	LPT1	LPT2	LPT3
ADDRESS	3bc	378	278
IRQ	7	5	5 or 7

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