Geeks in Paradise | Brian Chee » Bluetooth Serial Dongles

September 01, 2006 | Comments: (0)

Bluetooth Serial Dongles

TAGS: Toys and tools

Anyone that's had to setup an enterprise grade network device knows about yea ole box of unknown serial cables. The serial cables you use once or twice to do the initial setup, and then are tossed into a box along with the rest of the console cables. So I was quite excited to find three very different solutions for BlueTooth SPP (Serial Port Profile) devices.

The first unit I played with was from IOGear:

Serial Adapter with Bluetooth wireless technology
Model # GBS301

Froogle Search: $59.78 to $159.40 with MSRP at $99.95/each

 

The IOGear was the first one the Interop NOC gang found, we also found out pretty quickly that the 100meter range was only applicable when you were already paired with the unit. In order to do the initial pairing you had to be quite close. In most cases within a couple meters. So we figured that an external battery would be perfect, except that the power connector was quite small and more than a bit difficult to find. Joel finally found a supply and found it just as cheap to order a dozen, as it would for one. So with a battery and a zener diode it wasn't hard to drop the power down to the 5volts this unit wanted. The rubber band with the battery did make things a bit clunky.

Next up was the unit from Rovingnetworks.com

Model# Blueport-XP
Blueport II plus integrated re-chargeable Lithium Battery pack provides totally wireless connectivity for up to 30 hours on a single charge
Froogle Search: $196.47 to $199.95 with MSRP at $199.00

The most polished of the units I tried out, but also the most expensive (based upon MSRP) this unit has a removable antenna (stub) and an internal lithium battery providing upwards of 24hours of operational juice. Changing from DTE to DCE involved opening the unit up and swapping a set of jumpers. Though in all fairness, how many folks are really going to want to change it from the default DTE setting. Considering this is exactly how a PC serial port is setup. We tried this in a pretty RF noisy environment during the setup for the Interop trade show, and this unit worked flawlessly. This unit comes with a power brick that can also power the unit while the battery is charging. With nice bright LED's on the side of the unit, it was pretty easy to see at a distance what the BluePort's status was.

Also from Rovingnetworks.com

Model# Firefly
Firefly enables wireless connections to any legacy serial port and supports bi-directional RS-232 signaling at a rate of up to 464Kbps.
Froogle Search: $99.95 for one, to $179.99 for a pair with MSRP: $99.00

 

Almost identical in weight, but a bit smaller than the IOGear GBS-301 is the Firefly. Using the exact same power brick as the BluePort-XP the firefly was found most often in google/froogle sold as a pair. Very simple to pair as a cable replacement, so selling them as a pair makes a lot of sense. Interestingly enough, RovingNetworks.com also OEM's their Bluetooth modules and rounds out their product line with a Bluetooth 8bit 16channel A-to-D converter called the BlueSentry, along with a USB BlueTooth interface called the BluePlug and a BlueTooth to Ethernet access point.

The last unit to arrive is from BlueConsole.com
Model# BC-02
BlueConsole2 Adapter with RJ-45 (Cisco/DEC)
Froogle Search: not found, with MSRP at $129.00
Serial shell kit: $22.00

The BlueConsole2 is a truly interesting implementation of serial over BlueTooth. If you're using Cisco/DEC style consoles over RJ-45's, you simply plug in the BlueConsole2 into the console port and it gets all the power it needs to run the full 100meters. Their serial shells can be ordered either individually, or as a kit. For the most part, you may be able to use your existing console adapter shells. NOW THE BIG DIFFERENCE! Instead of a rechargeable battery that could go flat in your tool kit, BlueConsole instead has mounted a 9-volt transistor battery clip on the back end of the case. So even if your console port isn't Cisco/DEC RJ-45, you can still keep the unit running AND PAIRED with an external battery. This way you can pair with the unit at your desk, and then wander up to 100meters away to the network device that needs configuration changing.

Another big difference between the three vendors is in compatibility/installation guides for operating systems. By a large margin, the BlueConsole folks have put in a huge effort into setup guides for WinCE, Windows Mobile, Linux, Mac OSx, etc. So while I wasn't wild about their fairly cryptic commands to change the baud rate, their answer was that they're putting the finishing touches on a GUI utility that would take much of the pain out of the AT commands to set registers for baud rate, parity, etc.

All in all, I feel that battery powered units fit the bill much nicer in the case of a roving sysadmin trying to deploy switches around the enterprise. The powered units kinda miss the point in that as a serial cable replacement, they're not exactly cheap. I can see using them for instrumentation, and permanent installs but not for the roving sysadmin. For the engineers that slaved away designing the power units, my apologies. However, I tend to be that roving sysadmin quite a bit and the battery power units just feel right.

So while the tech support folks at BlueConsole reminded me that the serial port speed over BlueTooth is irrelevant I keep hoping that the BlueTooth standard will evolve so that the Serial Port Profile (SPP) can also include a standard set of API's that allow applications running on the host OS to change the serial parameters just like you can now do with physical serial ports under Windows or Linux. For now changing the baud rate will either involve an "AT" style command (ala the old Hayes AT command set) or the flipping of a DIP switch.

Just before posting, the BlueConsole folks sent me their pre-release serial parameter console tool fresh from a compile. So while we toss some email back and forth on what libraries I'll need to have for the pre-release testing, optimistically the jpg they sent me looks VERY promising. I'll pass on posting it, since it's not in general release yet, and I don't want to give their competitors a leg up on them.

Posted by Brian Chee on September 1, 2006 01:15 PM

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