Universal Serial Bus(USB) Devi

Universal Serial Bus Device Class Definition for Printing Devices

The Universal Serial Bus (USB) is a communications architecture that gives a PC the ability to interconnect a
variety of devices via a simple four-wire cable. One such device is the printer. Traditionally, printers have been
interfaced using the following technologies:
• Unidirectional parallel port
• Bi-directional parallel port
• Serial port
• SCSI port
• Ethernet/LAN
There are other, more sophisticated printer interfaces, but the ones previously listed are the most popular. USB
offers a much greater throughput capability than the serial port and is comparable in speed to the parallel port. This
makes both parallel and serial printers good candidates for interfacing with USB.
1.1 Scope
This document fully describes the Printer Class of USB devices, including:
• The Printer Class subclass and protocol.
• Device, configuration, interface, and endpoint descriptors.
• The USB standard requests used by printer devices.
• The USB class-specific requests and responses used by printer devices.