Parallel Port Mode

Common Options : Normal (SPP), ECP, EPP, ECP+EPP

Quick Review

By default, the parallel port is usually set to the Normal (SPP) mode. SPP stands for Standard Parallel Port. It is the original transfer protocol for the parallel port. Therefore, it will work with all parallel port devices.

The ECP (Extended Capabilities Port) transfer mode uses the DMA protocol to achieve data transfer rates of up to 2MB/s and provides symmetric bidirectional communication.

On the other hand, EPP (Enhanced Parallel Port), now known as IEEE 1284, uses existing parallel port signals to provide asymmetric bidirectional communication. It was also designed for high-speed communications, offering transfer rates of up to 2MB/s.

As you can see, SPP is a very slow transfer mode. It should only be selected when faster transfer modes cannot be used (i.e. with old printers or scanners). With modern parallel port devices, the ECP and EPP modes are the transfer modes of choice.

Generally, because of its FIFOs and the DMA channel it uses, ECP is good at large data transfers. Therefore, it is the transfer mode that works best with scanners and printers. EPP is better with devices that switch between reads and writes frequently (like ZIP drives and hard disks).

However, you should check your parallel port device's documentation before you set the transfer mode. The manufacturer of your parallel port peripheral may have designated a preferred transfer mode for the device in question. In that case, it is best to follow their recommendation.

If the device documentation did not state any preferred transfer mode and you still do not know what mode to select, you can select the ECP+EPP mode. If you select this mode, the BIOS will automatically determine the transfer mode to use for your device.