SEPTEMBER 6--The Universal Serial Bus (USB) Implementers Forum (Santa Clara, CA) has released the On-The-Go Supplement to the USB 2.0 Specification. This supplement defines a method for portable devices to expand upon their basic personal-computer (PC) connectivity by communicating directly with selected peripherals. The USB standard was initially designed to provide a common interface between a PC and its peripherals. Today many peripherals such as MP3 players, digital cameras, personal data assistants (PDAs), and cell phones are taking advantage of the USB's low cost, high speed, and widespread host port availability.
As portable devices increase in popularity, there is a growing need for them to communicate directly with each other when a PC is not available. The On-The-Go Supplement addresses this need for mobile interconnectivity by allowing a USB peripheral to have limited host capability to communicate with selected other USB peripherals, a small USB connector to fit the mobile form factor, and a low-power feature to preserve battery life.
A device with these features is referred to as a dual-role device and can take on the role of either host or peripheral when connected to other USB devices. Unlike a PC, a dual-role device is not required to support all possible types of USB peripherals. However, each USB On-The-Go product must operate as a peripheral with existing PCs in accordance with the USB specification.
Once adopted, the On-The-Go Supplement will allow manufacturers to develop devices with exciting new capabilities. An MP3 player could be connected to another MP3 player to transfer music files. A camera could be connected directly to a printer to print out a picture. A PDA could be connected to a cell phone to enable mobile web surfing.
Publication of the 0.9 revision of the supplement, available on the Web: www.usb.org/developers/onthego, is viewed by the industry as a signal to manufacturers that the essential technical content is complete. Ratification of the 1.0 revision of the supplement is expected by the end of this year, after a public-review period. The first product shipments based on the specification are anticipated in 2002.