Everything USB

Breakthrough: USB 2.0 & USB OTG

March 25th, 2005
By John Koon, Senior Industry Analyst, Tech Idea International

USB 2.0: 480Mbps Speed Boost

Hi-Speed USB Certified logo

Perhaps the most significant breakthrough for USB was the introduction of USB 2.0 which increases the bus speed from 12 Mbps to 480 Mbps, a forty-fold increase. The original USB specification called for 12 Mbps for full-speed and 1.5 Mbps for low-speed (for human interface devices such as mouse device). These speeds were not sufficient for certain applications that operated simultaneously, such as video, audio, and printing, where the bandwidth limitation becomes an issue. The new Hi-Speed USB mode of USB 2.0 solves this problem. At 480 Mbps, tasks like downloading digital photos can be accomplished in seconds rather than minutes.

USB OTG: Peer-to-peer Connectivity

Hi-Speed USB OTG Certified logo

USB OTG Certified logo

The goal of the USB OTG Working Group was to create a standard, like USB, that uses a simple cable and miniaturized connectors that will fit comfortably into the new smaller sized devices. Also, for a USB OTG device to connect to other devices without the use of a PC will require the peer-to-peer capability, much like that in IEEE 1394. As this feature is lacking in USB 1.1 and the original USB 2.0, the USB OTG workgroup has incorporated this feature to the USB OTG standard, which became an addendum to the USB 2.0 specification.

USB OTG will simplify the interconnection of these small devices as one cable will connect between all USB OTG devices, which will work together much like USB. Thus, USB OTG will enable consumers to print photos directly from a camera, and sync data with a PC or other back-up unit. The ability to connect to many different accessories also will benefit consumers, who will have a greater selection of devices. For example, a PDA keyboard with a USB OTG interface will be compatible with any brand PDA with a USB OTG interface.

While connection without the PC is attractive, emerging wireless standards such as Wi-Fi and Bluetooth are providing a preferred method of connection. For example, users can print photos wirelessly. With the advance in Wi-Fi and Wimax, cell phones are expected to be able to download files and to synchronize anytime and anywhere. OTG may be facing an uphill battle in gaining acceptance.

Overall

The outlook for USB is quite positive. USB has become the interface of choice for peripheral developers due to its auto-configuration and ease of use features. Today USB ports are available in every PC, laptop, palmtop, industrial PC, modular PC, tablet PC, and PDA, and many consumer products like MP3s, digital recorders, and digital cameras. The popularity of USB adapters, such as USB-to-Bluetooth, USB-to-serial, and USB-to-wireless control, will continue to increase, and USB flash memory devices, which come in many different forms like key chains and wristwatches, have replaced floppy disk drives.

The USB Revolution

Wireless USB: Cutting the Wires

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