Bluetooth brings era of cable-free networking

Imagine transferring a list of contacts from your mobile telephone to your desktop–without cables. Or accessing a corporate network without an Ethernet card; or using your mobile phone to buy food from a vending machine or a store. That is the promise of Bluetooth.

This short-range wireless technology uses a low-power radio frequency to connect a range of devices for file sharing and ad-hoc networking across distances up to 33 feet (300 feet with an amplifier).

An open standard backed by a consortium whose 2000 members include L.M. Ericsson Telephone Co., IBM Corp., Intel Corp., Motorola Inc., and Nokia Corp., Bluetooth has for several years been the most loudly trumpeted imminent arrival in instant wireless networking. But apart from a couple of notebooks with Bluetooth ports, products have been slow to appear.

We tested two of the first non-notebooks to use Bluetooth: an Ericsson cellular telephone with a Bluetooth wireless headset, and a pair of Toshiba Corp. Bluetooth PC networking cards. Our conclusion: Bluetooth works, but it is not without some flaws.

Wireless networking protocols such as HomeRF and 802.11B are widely used for connecting notebooks and desktops, but Bluetooth offers some additional benefits. Because its battery power consumption is minimal, it can work on small devices. It can, for example, hook a mobile phone to a PDA or a laptop so the phone will act as a wireless modem. A Bluetooth headset permits hands-free calling without the constraints of a wired earpiece. On a laptop, Bluetooth allows wireless file exchange and network access.

Bluetooth pays a performance price for its power conservation. With an underlying speed of only 1Mbps, Bluetooth’s real-world throughput is about 725Kbps. That’s fast enough for voice and audio data but not for full-motion video, which the next revision of 802.11 will support. Version 802.11A has a speed of 54Mbps but won’t be available before mid-2001. HomeRF, which currently tops out at 2Mbps, is expected to attain 10Mbps at about the same time.

Bluetooth is unlikely to supplant 802.11B, but it should render infrared obsolete, since it eliminates that technology’s line-of-sight requirement. It operates in the same 2.4-GHz frequency range as 802.11B, HomeRF, and some microwaves, so it may encounter interference in locations where other wireless technologies are in use.

Bluetooth in action

Bluetooth devices are supposed to be interoperable, but in our tests, not every connection was compatible.

Setting up the Bluetooth wireless headset to work with the Ericsson phone required some effort. After we plugged the DBA-10 Bluetooth adapter into the T28 World phone, we had to browse menus on the phone’s display to find out how to connect Ericsson’s HBH-10 wireless headset.

The headset transmits and receives audio through the phone fairly well and, though a bit bulky, is comfortable for walking. In a building with poor phone reception, you can leave the phone in the best reception area available and roam from there. In our tests, the headset delivered clear sound over Bluetooth’s 30-foot range. Its signal traveled adequately through one wall.

The second product we examined, Toshiba’s PA3053U PC Card, is a PC Card with a flat antenna and a status light. The card comes with driver software, a “Bluetooth neighborhood” browser for handling interdevice communications, and a collaboration tool called SPANworks 2000.

We installed a card on each of a pair of IBM ThinkPad notebooks running Windows 98 and used the Discovery command on the Bluetooth browser to get them to recognize each other. After establishing this local network, we shared printers and moved files between the laptops at about 270Kbps. At that rate, transferring a 10-MB file would take about five minutes. The Bluetooth browser can also set up connections for sharing electronic business cards or accessing a remote dial-up connection. Our efforts to transfer files using OBEX (an object transfer protocol for Bluetooth) were unsuccessful.

The SPANworks 2000 application, a tool for impromptu meetings, worked as advertised. We found it easy to share files, chat and view a common PowerPoint presentation.

Getting Bluetooth to work across device platforms was not easy. We did “discover” the Ericsson phone, but we couldn’t connect it to the laptop. The headset went unrecognized altogether. It may be some time before different vendors’ products really work seamlessly together and share a common look and feel.

Still on the way

By mid-year, Bluetooth will start appearing in phones, pagers, Palms, Pocket PCs, desktops, notebooks, network adapter cards and more PC Cards. Microsoft will build Bluetooth support into the successor to Windows Millennium and 2000, code-named Whistler. Cahners In-Stat Group predicts that more than a billion Bluetooth products will ship by 2005.

But early adopters will pay a premium. Toshiba’s PC Cards cost US$199 each – more than many HomeRF and 802.11B cards – and the T28 phone runs US$299 without the headset and adapter, for which pricing has not been set. A similar headset from GN Netcom is expected to cost US$499 when it ships next year.

Nevertheless, prices should eventually come down. And once the interference and the other incompatibilities are resolved, Bluetooth should eliminate a fairly large share of the cable clutter in our lives. That will be progress that you won’t have to trip over.