bluetooth specifications
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Thread: bluetooth specifications

  1. #1
    AO übergeek phishphreek's Avatar
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    bluetooth specifications

    I'm a little confused as to the specifications of bluetooth.

    I'm aware of the different classes.

    Class 1 ~330ft (100m), class 2 ~33ft (10m), etc.

    Do they work together?

    Example:

    If a place like star bucks puts in a class 1 "access point?" with a range of 330ft and I go in there with my palm with the range of 33 ft, will they work together? As long as my palm is in range of the signal put out by their "access point?" ???

    It would make sense to me... but bluetooth is pretty new to me.

    Or, would it be unlikely that they'd offer that service because it would conflict with the 802.11x ap that they may have installed?
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  2. #2
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    I'm no expert in this field but i think you may be confusing bluetooth and wifi. I have not heard of any bluebtooth equipment that will work over 10m and in my experience you would be lucky to get it to work over 10 ft. I have a pocket pc that i link to my phone via bluetooth to access the net and anything over a few feet and you can forget it.

    I think to use a ( whats called a hotspot) wireless access point at starbucks you need to use a wifi compactflash card which is very different than a bluetooth card. I maybe wrong in this assumption but i have never heard of a bluetooth hotspot.

    Bluetooth as a technology is bloody awfull at the moment hardly any of it works as you would expect it to. To give you an example i brought a bluetooth fone, thinking that i could then get a bluetooth pcmcia card for my laptop, and in the end i did, but nokia fones use a push technology that not all cards exept and now i have my pocket pc wityh a bluetooth compact flash card syncronizing with my laptop via bluetooth can't be done ( though it should be possible). Where if i i had gone the wifi route it would be possible.

    As for whether bluetooth and wifi are compatable with each other the answere is no the will not work together. You can howerever get equipment that have both wifi and bluetooth built in, you just cant work the to at the same time.
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    I have a friend who a while back decided to join the BlueTooth concortium just for the heck of it. He handed me about 40 pages of printed material that he already read the next day... I haven't asked him about this, so below is just my assumption...


    1st - Like jinxy, I haven't heard of BlueTooth devices going beyond 10meters, since it is designed to be low power and of about 300kbit datarate.

    2nd - If they did make something like that, I would *assume* that it would be backwards compatible. Keep in mind I haven't read anything talking about that Class 1 of 330ft? Perhaps you are talking about WiFi, which has that range, but BT and WiFi are incompatible. Infact, they probably intefere with each other. Same thing with Microwaves and 2.4Ghz phones, but soon newer Microwaves will have some magnets placed throughout the Magnetron to clean up the emited Microwaves to hopefully not intefere with these technologies...


    For a while it seemed that BT could have been the next big thing, but the papers I browsed over seemed to say that BT wasn't designed to take over WiFi. Instead, it was designed for a PAN, or Personal Area Network. That 10meter "Bubble" would be just enough for all of your gadgets to communicate with each other, and your friend's gadgets if needed. Since it was for all of your tiny tech gizmos, they decided that power consumption was a priority, they decided that BT would have limited range (10m) and low datarates (300kbit/s?). The paper went on talking about how much power other Wireless technologies such as WiFi use more power with more range (100m) and high datarate (11mbit/s), and how Telestrial Satelite systems for those Satelite Phones and stuff used a lot of power, but to *reduce* it used low datarates (64kbit?) for that distance (distance to a telestrial satelite?). If they wanted to, they could increase power consumption and datarate, but it was my understanding that BlueTooth was for your "Personal Network", and thus would never go 100meters since power requirements would go up too much.

    In the US, BT didn't catch on. Same in Japan I think, but it was marketed differently. In early 2001 or so, BlueTooth phones were apparently marketed as being able to play Movies over your wireless network, but I think those phones were eventually discontinued, as my ancient 2000-2001 era phone that plays ATRAC-3 (Sony's Propietary Format, like MiniDisc) was soon discontinued. In Europe though, I think BlueTooth is doing a bit better, and Sony decided to allow the NX-73V Clié to have built-in BlueTooth, and to only market the really expensive BlueTooth Memory Stick over there...


    I'll ask my friend if he heard anything about 100meters for BT. I really doubt it though...

  4. #4
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    Okay, my friend got back to me. In short, there is a BlueTooth 1.1 and 1.2 (new) specification. Neither of them offer the 100meters you were asking about. They are both the same speed (which I think is 1mbit?) and same range, 10 meters. So, since the class you mentioned does not exist, it does not work.

    Also, I don't think Star Bucks isn't a part of the BlueTooth Special Interest Group, so I doubt that they would be able to offer a BlueTooth service. My friend also mentioned that the Interference between WiFi and BlueTooth (and other 2.4GHz things) isn't as great as you may think, since BlueTooth subdivides the frequencies even more, and hops among them. Of course the short range probably is a limiting factor in offering this sort of service...

    Hope that helps.

  5. #5
    AO übergeek phishphreek's Avatar
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    Thanks for the replies... but I'm almost certain that there IS a 100m bluetooth class...

    Bluetooth Range in Relation to Different Power Classes

    Three power classes are available for bluetooth. Classes 1,2 & 3 , they have the following characteristics:

    Device Power Class Max Output Power (mW) Max Output Power (dBm) Expected Range (?Obstructed Environment?)
    Class 1 100mW 20dBm 100m
    Class 2 2.5mW 4dBm 10m
    Class 3 1mW 0dBm 10cm

    A definitive definition of ranges based on power class is hard to come. Not only due to power & device differences but whether you measure open space or close office.
    What is the range of Bluetooth transmitter/receivers?

    Bluetooth is designed for very low power use, and the transmission range will only be 10m, about 30ft. High-powered Bluetooth devices will enable ranges up to 100m (300ft). Considering the design philosophy behind Bluetooth, even the 10m range is adequate for the purposes Bluetooth is intended for.
    Source

    My main question is, do the different classes work together? Can I use my class 2 device with a class 1 device?
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  6. #6
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    This is the first time my friend heard of it, thanks for the info. I did some research, and this is what I found.

    The only difference is the power in the Antenna. Most BT devices are the normal 10meter range BT (Class 1 or 3?). The long range ones are Class 2 & 3 (or 2 & 1?), anywhere from 30 to 50/100 meters. Antenna sensitivity is also different, and yes can mix between the classes. The BlueTooth standard is still usually Bluetooth 1.1. That is where my friend got confused, the Bluetooth standards. 1.2 is the new standard, and it is backwards compatible so no fears there.

    I don't know if they got the explanation mixed up, but here it is...

    "Class 3 to Class 3 radios is 10 Meters; Class 2 to Class 2 is
    about 30 Meters and Class 1 to Class 1 is anywhere from 50 Meters to
    100 Meters (the Bluetooth spec says a Class 1 radio is simply any radio
    that has at least 7dBm and they go all the way to 20dBm so it really
    just depends on the output power to what range they can achieve.) Now
    that is standard out of the box specifications, but you can also get
    weird combinations like Class 3 to Class 1 and get around 30 meters or
    so. There are also a lot of differences with different types of
    antennas, so if you put special antennas then you can get further (we
    achieved 60-80 meters between two class 3 radios with two high power
    antennas.) You will also notice different range in direct line of sight
    verses through interference. Finally, light and other devices can
    sometimes cause slow down like a very high power color laserjet printer,
    for example. <<it's all about physics>>"
    http://www.techbase.ca/reviews.php?review=pm2002

  7. #7
    AO übergeek phishphreek's Avatar
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    Tim_axe: Thanks for the info. I couldn't find an exact answer anywhere I looked.

    I figured they'd be compatable, but I wanted to be sure.

    I want to get a class 1 usb BT device for my house to use with my palm.
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