USB set to tackle 1394 peer-to-peer advantage

USB On-the-Go to eliminate host PC

Universal Serial Bus will soon get the one feature that separates it from IEEE 1394: peer-to-peer operation.

The specification, dubbed USB On-the-Go, apparently has the backing of Palm, Microsoft, Intel, Nokia, Hewlett-Packard and others, though it's primarily being driven by TransDimension, which specialises on Bluetooth and USB host controller silicon. It is intended to be an adjunct to the current USB 2.0 spec.

When Intel first announced USB, back in 1996, 1394 proponents saw clear blue water between the two bus standards. The differentiator was speed - 1394, also known as FireWire and iLink, was considerably faster than USB, running at 400Mbps, compared to just 11Mbps for USB.

USB 2.0 changed that, by upping the bus' throughput to 480Mbps, but FireWire fans could always point out that while USB required a host, 1394 connections can be made directly between devices. USB 2.0 silicon is already sampling, with peripherals based on the new spec. due to ship during the first half of this year.

Now USB will get that feature too, through USB On-the-Go. Yes, it's a silly name, but it should finally allow, say, a USB digital camera to dump pictures straight to a USB printer.

The system won't make USB a true peer-to-peer bus. Instead, devices will negotiate with each other to elect an ad hoc host. The point is, though, the chain will not need to include a host PC.

The USB On-the-Go spec. has yet to be approved by the USB Integrators Forum, the standard's governing body. However, according to TransDimension's On-the-Go Web site, a preliminary specification is expected to be made available this summer. Assuming, of course, that the USB IF gives the spec. its blessing.

If that timeframe is kept, we could see a final specification a further six months or so down the line, with silicon sampling a year after that, probably mid to late 2002, based on the time it's taken to get USB 2.0 from draft to shipping product.

That leaves plenty of time for 1394 to become well established throughout the consumer electronics world, thanks to schemes like the widely supported 1394 and Java-based Home Audio Video Interoperability (HAVi) initiative. ®

Related Link

The USB On-the-Go homepage

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