Bluetooth – Breaking The Cables That Bind PCs – THG.RU

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Breaking The Cables That Bind PCs” –>

Look Ma, No Cables!

Network cables, PDA connector cables, printer cables, keyboard and mouse cables – the list of cables found at a standard PC workstation goes on and on. Not only are all of these cords inconvenient and hard to store, they have something else in common – they can all be replaced with wireless transmission technologies.

The most common technologies that do away with cables are infrared, Bluetooth and Wireless LAN. Other than the fact that they replace all the cables mentioned above, these technologies have little in common. The applications and underlying technologies vary widely within this group.

The Wireless Pioneer – Infrared

The least expensive of all is the common infrared port. Most notebooks and cell phones come furnished with an infrared receiver, while upgrade sets for desktop PCs can be had for as little as $50. Moreover, many laser and inkjet printers come furnished with an infrared interface.

Unfortunately, though, infrared (IrDA) is as inconvenient as it is common. The infrared ports on the communicating devices have to be precisely aligned with one another. Otherwise, the connection, which at 4 Mbps is very fast, will abort abruptly. To make matters even more complicated, you need a line-of-sight connection, which means that any obstacles between the devices will prevent them from connecting via IrDA. Yet another limitation is the relatively short maximum distance: the devices can be no farther from one another than a half meter.

With these restrictions in mind, infrared is only advisable for anybody who wants to get rid of some cables without investing a lot of money. However, if you want to connect your notebook and cell phone wirelessly on a more frequent basis, you’d be better advised to opt for the more flexible Bluetooth technology.

The Universal Cable Killer – Bluetooth

Bluetooth has been designed to replace cables for a whole slew of different devices. From cell phones and printers to notebooks and PCs right up to PDAs, Bluetooth (BT) allows these devices to communicate with one another wirelessly, transmitting at rates of up to 1 Mbps.

The technology has been tweaked to require as little electricity as possible. Virtually all devices for which BT has been designed run on batteries. This makes it essential that Bluetooth use only minimal amounts of this precious electricity. This also cuts down on its reach: Bluetooth devices in the power-saving class 2 (3 to 30 milliamperes required to send) cannot transmit past 10 meters.

The advantage of BT over Infrared is that it’s based on radio, eliminating the need for line-of-sight connections. So you can keep your cell phone in your pocket during the online session since the Internet data will still make it onto your PDA or the notebook via Bluetooth.

However, this technology is still not very common. At present, there are only a few cell phones, printers and notebooks that come furnished with Bluetooth. Nor are BT expansions for PCs and notebooks affordable for the public at large, with prices between $90 and $250.

If you plan to connect various devices such as cell phones, PDAs and notebooks wirelessly, Bluetooth is the technology for you. No other technology is as flexible or as compatible with so many different devices.

The Pro’s Solution – Wireless LAN

Though it also transmits in the 2.4 GHz frequency band, Wireless LAN (WLAN) has an entirely different area of application than Bluetooth. It has been designed to transfer larger amounts of data via the IEEE-802.11b standard with a theoretical maximum rate of eleven Mbps. Because of its complexity and its high power consumption, WLAN isn’t a candidate for connecting a mobile phone wirelessly.

And while its real measured maximum rate of 5 Mbps isn’t even in the same league as a wired 100 Mbit Ethernet, WLAN is still fast enough to copy hefty files to a server, to surf the ‘Net via a fixed line or DSL, or to send e-mails with attachments.

WLANs can transmit up to 30m within buildings. The actual distance depends greatly on the construction of the walls and ceilings, with gypsum-board walls hardly causing WLAN to break its stride, while solid stone walls can put a serious dent in radio traffic. At the same time, the reach of WLANs is a security problem, since snoops can receive them outside of buildings, too.

But WLAN isn’t suitable just for transmitting data and surfing online. By now, WLAN printer servers have introduced conventional printers to Wireless LAN. Added to that are Pocket PCs, whose WLAN Compact Flash cards connect them wirelessly, as well.

WLAN is ideal for smaller offices or private individuals with a vested interest in wireless flexibility. At $600, the costs of basic set-up, consisting of an access point or DSL router and PC cards, might be steeper than a wired connection; however, Wireless LAN can be expanded or disassembled in no time flat. On the other hand, WLAN is still too slow if three or more PCs are to be connected wirelessly so that they can constantly transfer large quantities of data. Its successor has already left the development laboratories and devices are available in the US, but it will be some months before the 54 Mbps technology hits the markets world wide and we can report about field experience.

Radio Traffic with Bluetooth Hardware

Bluetooth promises wireless freedom for PCs, notebooks, cell phones, PDAs and other devices. But the test shows that PC cards and USD dongles don’t always work together smoothly.

Bluetooth (BT) is an attractive option for both traveling notebook owners and desktop PC users. Whether BT is used to synchronize a PDA with a notebook, or to connect a PC to a printer, it eliminates cables in both cases. However, only the occasional notebook – and nary a desktop computer – comes with the necessary BT technology pre-integrated. So users have to turn to USB dongles or PC cards. The laboratory put five BT USB dongles and five PC cards that are readily available in Germany through their paces. TDK took the gold in both categories. The TDK Bluetooth products got excellent scores for their mature software and outstanding user-friendliness.

The Stollmann USB dongle is an exception in the testing field. Stollmann presents itself as an OEM (original equipment manufacturer), whose products are sold by other companies under their brands. Which companies will be offering the Stollmann dongle was still not clear when we went to press. But the manufacturer will be providing information to interested parties (over the phone or via email) about partners who will be selling the dongle.

So Much Depends on the Control Software

There are huge differences in the ever-important control software for BT devices. The software is the actual console for the Bluetooth components and is used to control all aspects of the hardware, from establishing and terminating a Bluetooth connection to defining the passwords needed for the connections. These passwords are indispensable because they are the only way to block unauthorized access to the Bluetooth devices. It’s up to the software producer to supply users with well-designed control software that allows these features to be used conveniently. And that’s where the main difference lies between the individual BT adapters. Whereas TDK, for example, has brought Widcomm’s easy-to-use software on board, Mitsumi ends up irritating its customers with a poorly designed program.

The TDK software, being similar to Windows Explorer, can be operated intuitively by any Windows user. Searching for other BT devices is as effortless as establishing a connection. A window appears in the taskbar informing the user if the opposite terminal requires a password. The advantage to being located in the taskbar is that no other window can hide this important dialog box.

The control tool for the TDK adapter has no problems interfacing with the Nokia 6310, a telephone whose Bluetooth implementation is far from error-free, to the point of being a frequent impediment. Despite this problem, the TDK software easily connects to the cell phone.

In contrast, linking the Mitsumi software and the Nokia phone is a huge headache: users only have a fraction of a second to enter the PIN code needed to connect the phone. This often turns into an exercise in patience and a test of hand-eye coordination, with success often following on the heels of many failed attempts.

Bluetooth is Secure

Several factors are supposed to protect Bluetooth from snoops. The radio technology changes frequency 1600 times a second (called frequency hopping) in order to block simple eavesdropping. Also, users have the option of using 128-bit encryption, foiling the plans of even professional snoops. While it’s theoretically possible to break this encryption, there have been no reports of any successful attack thus far. Anyway, BT connections are harder to tap than Wireless LANs: because the reach is limited to 10 meters, malfeasants have to get extremely close to be able to listen in.

No Profile, No Service

Each BT device proffers its services through special Bluetooth profiles. For example, there exists a Dial-up-Networking profile (DUN), especially prevalent among mobile phones. Another common face is the Serial-Port profile, used to connect to printers, for example. If a device doesn’t recognize a profile, users won’t be able to use the services behind the profile. This can be a real problem if the File-Transfer profile is missing. Since this profile allows files to be copied between notebooks and PDAs, it ought to be very common. So it’s all the more incomprehensible that some candidates don’t recognize the profile. For example, users of the Com-One USB dongle and the Sphinx card have a nasty time copying files via the Serial-Port profile and the direct-connection software integrated in Windows 98/ME. This is an excessive detour.

User-friendliness is Key

The quality of a Bluetooth adapter isn’t dependent on the hardware. None of the devices in the test had a problem establishing a Bluetooth connection. That said, not all the opposite terminals connected reliably, which is less a question of hardware than it is of the user-friendliness and the capabilities of the control software. That is what truly determines whether the adapter is effective in day-to-day use.

TDK took a step in the right direction by using the Widcomm software. No other USB dongles or PC cards offer such an intuitive interface as the TDK devices.

Test models – 5 Bluetooth PC Cards

3Com Wireless Bluetooth PC Card

Anycom Bluetooth PC Card

Sphinx Pico Card

TDK PC Card Go Blue

Xircom Realport 2 Bluetooth

Test models – 5 Bluetooth USB Adapters

3Com Wireless BT USB Adapter

Com One Bluetooth USB

Mitsumi USB Adapter

Stollmann USB Dongle

TDK USB Adapter Go Blue

Testing Procedure & Evaluation

The Bluetooth USB dongles and the Bluetooth PC cards underwent the same testing procedure. The test considers user-friendliness, performance, service and features. All the Bluetooth devices performed the test while installed in a Compaq Evo N600C notebook running Windows 2000. The compatibility of the devices with Windows XP was checked in a Baycom Worldbook 4 Pro.

Being Friends with Users

The grade for user-friendliness is based on the quality of the control software, the installation steps for the BT device and the documentation. The laboratory experts also checked what languages the manual includes and whether it is supplied in hard-copy or CD only.

The performance grade is equally important. The lab engineers measured the transfer performance by copying a 4.5 MB file to a reference terminal via Bluetooth and then reading it out again. The testers also recorded how long the devices needed to send a file via Bluetooth to the ink-jet printer Hewlett-Packard Deskjet 995C. This result also influences the performance grade.

The final portion of the performance grade came from the compatibility course. All the devices tested had to establish a wireless connection to a set number of Bluetooth terminals and then use their services. The testers awarded a point per terminal for devices that were able to use services without errors.

The features grade was based on the number of drivers included with the adapter. The testers also checked whether the driver software was supplied on a CD or at least available on the manufacturer’s website for downloading.

Test Results in Detail

One trend was true for all the devices, be they PC cards or USB dongles – the major differences were not found in the hardware, but in the number of profiles and the control software.

It’s emblematic of the difficulties Bluetooth has to struggle with despite its long history of development that virtually every adapter shows a message during the printing process. A window noted that an error had occurred during printing and asked whether to abort the job. When the testers didn’t respond to the message, the printer had no trouble printing the document. Yet, ironically, it was clicking on “Stop” that actually prevented the printer from doing what the window had claimed it was incapable of. At least the 3Com manual mentions the phenomenon.

The Decisive Element: the Control Software

As the comparison showed, the quality of a Bluetooth (BT) PC adapter depends almost entirely on the user-friendliness of the control software. For example, TDK Systems shows its competition what perfect software should look like. The program, developed by Widcomm, blends in perfectly with Windows Explorer, making it a snap for any Windows user to operate. Users control all the features of the adapter in this environment, including searching for other devices, connecting to other devices or copying files.

In contrast, Anycom offers three separate programs: one to control the adapter and to establish connections; one for printing; one to copy files. While the actual programs are easy to use, the separation itself is awkward, especially since the programs don’t automatically sever an established connection to an opposite Bluetooth terminal, thus blocking the device for other connections.

Nor does the Com-One software sever the connection, which is particularly annoying when printing to the HP Deskjet. So even if the Com-One adapter isn’t transmitting a document to print, other BT computers are prevented from accessing the ink-jet printer. In all other aspects, though, Com One is a paradigm of how to put the BT device into operation. After the driver has been installed, a wizard starts up, searches for all devices within reach and then, if desired, establishes a connection easily and immediately.

Profiles Determine Functionality

Bluetooth devices communicate with one another via profiles. For example, the HP printer offers the Serial-Port profile, which simulates a conventional COM port through which the printer receives print jobs. In addition to the Serial-Port profile, all the devices we tested recognize the Dial-up-Networking profile (DUN) to establish a dial-up connection online. Neither LAN access nor faxes constitute stumbling blocks.

Data transfer, on the other hand, is an obstacle. The adapters from Mitsumi, Stollmann, Com One and Sphinx don’t recognize the File-Transfer profile. That means that these devices can’t copy data – an enormous shortcoming for BT-PC adapters. Although the 3Com and Xircom do recognize the profile, the 3Com adapters only transfer files to other 3Com devices and the Xircom card is dependent on Pumatech’s Intellisync software for transferring files. Only if Intellisync, included with the card, has been installed on both sides, which is permitted in the license agreement, will the file transfer actually work.

The only BT adapters to copy data without any problems – or add-on software – were from TDK and Anycom. We found the difference in performance between the two devices to be considerable. While the two TDK adapters copied the 4.5 MB test file in 101 seconds, the Anycom card needed 166 seconds to perform the same task.

Compatibility is of the Essence

All the devices tested had to be able to contact reference terminals. The more successful connections, the more points the BT device received. The reference terminals were: an HP Deskjet 995C printer; an Ericsson T68 cell phone; a Nokia 6310 cell phone; a Palm m505 (with an Bluetooth SD card); and a Compaq Ipaq 3850 (with an Anycom Compact Flash card).

The adapters took anywhere from 60 seconds (3Com) to 92 seconds (TDK and Com One) to print the 4.5 MB image file. Overall, the results were impressive, considering that the file was transferred via a virtual serial port. The frustrating thing about the Mitsumi dongle is that after issuing a print command, you have to select a Bluetooth device in the control software to carry out the job. To make matters worse, the connection window doesn’t appear automatically in the foreground. So it’s easy to overlook the fact that you have to select a device, which effectively keeps the document from being printed.

All the devices tested were able to connect to the Internet via the T68 and to synchronize with the Palm and Ipaq. The Nokia 6310 was the only device to which the Mitsumi adapter was unable to connect. This is the only dongle where the PIN prompt disappears from the display on the cell phone in a fraction of a second. It took our laboratory experts a good while to finally establish a connection.

Our Recommendations

TDK PC Card Go Blue

TDK Systems is head and shoulders above the competition with its Bluetooth PC card. The card comes with the very same software as the USB adapter and is just as easy to use. Since the card is also a cinch to install, it has earned our recommendation despite its high price of $170.

TDK USB Adapter Go Blue

The control software for the TDK adapter is very mature, even handling problematic devices such as the Nokia 6310 smoothly. The adapter also supports all essential Bluetooth profiles, such as File-Transfer and Dial-up-Networking, making it universally compatible.

Features of Bluetooth PC Cards

Features of Bluetooth USB Adapters

¹⁾ File transfer only possible with 3Com devices
²⁾ File transfer and synchronization only possible with add-on software
³⁾e.g., on-site service

This article was written in cooperation with VNU Business Publications.