1. Parallel Port

2. Scanners communicate to their host computer using one of the following physical interfaces, listing roughly from slow to fast: Parallel port - Connecting through a parallel port is the slowest common transfer method.

3. Parallel port based Ethernet adapters were produced for a time, with drivers for DOS and Windows.

4. This data is then processed with some proprietary algorithm to correct for different exposure conditions, and sent to the computer via the device's input/output interface (usually USB, previous to which was SCSI or bidirectional parallel port in older units).