Chip maker Cypress has begun offering a wireless version of USB in a bid to pull the rug from under the feet of Bluetooth.
Cypress' WirelessUSB product is a $2.20 system-on-a-chip part that delivers USB 1.1 connectivity through the same 2.4GHz band that Bluetooth and 802.11b operate in.
By designing the system around typical USB 1.1 applications: low-bandwidth peripherals connected to a host computer with a short cable, Cypress has been able to narrow the chip's throughput requirements to 62.5kbps. That, in turn, has allowed it to offer WirelessUSB rather more cheaply than Bluetooth, the chief wireless alternative to printer cables.
Unlike Bluetooth, WirelessUSB provides a high level compatibility with existing USB human interface device software stacks, making it easier for peripheral and PC developers to roll out the technology. Cypress is primarily targeting keyboard, mouse and game controller makers, but it's not hard to see the technology being extended to other roles, such as wireless printing, where Bluetooth has had relatively little success.
As it stands, WirelessUSB isn't much use for some of other Bluetooth applications, most notable digicam picture transfers and PDA synchronisation, largely because these all demand more bandwidth than WirelessUSB can supply. Sync'ing a PDA using Bluetooth is slower than using a USB cable, but not enough to outweigh the benefit of eliminating cables. We're not sure the same is true of WirelessUSB.
Bluetooth also has momentum. There's a long way to go before Bluetooth could be said to eliminate the need for cables altogether - OS support isn't great (it's there, but not all the options are supported - try printing from the supposedly Bluetooth-friendly Mac OS X, for example) and plenty of peripherals have yet to integrate Bluetooth, particularly cheaper ones.
Price is the issue here, with Bluetooth chips costs under $5. Two-way WirelessUSB parts cost $2.20 now, but Cypress expects that to fall to under $1 over the next few years. At that price, peripherals vendors may well be tempted to go down the wireless USB route rather than choose Bluetooth. Though as with the other wireless technologies, getting it inside host computers, rather than dongling it on, is essential for real success.
In addition to the two-way part, Cypress is shipping a $1.95 transmit-only device. Both devices have a typical standby current of one microamp, which should improve devices battery lives. WirelessUSB incorporates a unique DSSS (Direct Sequence Spread Spectrum) coding scheme to ensure "robust" operation in the presence of 802.11 and Bluetooth networks. It also enables WirelessUSB to support thousands of devices in close proximity, Cypress said.
In separate Bluetooth news, Cambridge Silicon Radio said it has added an HID proxy capability to its BlueCore chipset. The upshot: a Bluetooth-connected mouse or keyboard can be used while the host system is booting up and before the OS has loaded.
Essentially, the software necessary to allow keyboard and mouse connections runs on the chipset, which presents itself to the host as an emulated USB device. That means the BIOS will recognise them, in turn allowing users to change BIOS settings or boot into 'safe' mode, something they'd otherwise need a wired keyboard to do.
When the OS loads, the chipset switches out of USB emulation mode and can operate as a regular Bluetooth device. ®