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  1. #1
    Regular Contributor
    Join Date
    Apr 2005
    Posts
    75

    Inquiry scan mode <-> Inquiry mode

    Hi,

    It seems that when an inquiry is started on phone A, during this time no other phone can detect phone A. Sometimes it is detected but this is not predictable.
    See also: http://discussion.forum.nokia.com/fo...hlight=inquiry
    So, when a device is in inquiry mode it can not be in inquiry scan mode. Is this right? Is there a way to overcome this, or if not is there a spec/doc that exactly say this?
    How could it be possible to execute a continious inquiry on two phones but ensure that they detect each other? This is what I want to do...

    Thanks for any help,

    Kurt

  2. #2
    Nokia Developer Expert
    Join Date
    Aug 2007
    Posts
    1,595

    Re: Inquiry scan mode <-> Inquiry mode

    Hello Kurt,

    when a device is in inquiry mode it can not be in inquiry scan mode. Is this right?
    Here's an explanation regarding:

    "..when two phones are simultaneously in inquiry mode, they become undiscoverable to each other which is due to the fact that, when in inquiry mode the Bluetooth radio bandwidth is completely consumed.
    ..
    When a Bluetooth device is in the inquiry mode, it continuously transmits inquiry packets and hops frequencies 3200 times per second. A device that allows itself to be discovered, regularly enters the inquiry scan state to respond to inquiry messages, hopping frequencies once every 1.28 seconds. In order to discover all devices, the device must spend at least 10.24 seconds in the inquiry mode. Once discovery has completed, the device behaves like other devices, entering the inquiry scan state periodically. When device discovery is followed by service discovery the minimum time to be spent in the inquiry mode is even larger."

    Source: http://www.cs.rutgers.edu/~iftode/smph04.pdf

    So in short: while doing discovery a BT device can't set itself discoverable.


    More about using Java with Bluetooth:

    http://developers.sun.com/mobility/a...luetoothintro/


    Regards,
    r2j7
    Last edited by r2j7; 2007-12-02 at 01:18.

  3. #3
    Regular Contributor
    Join Date
    Apr 2005
    Posts
    75

    Re: Inquiry scan mode <-> Inquiry mode

    Thanks for this information.

    I figured out that my application crashes on one phone after some time when two phones (6630) are continuously perform an inquiry. But this happens arbitrarily - sometimes everything works fine. It seems that the phone that was started first crashes.
    On N95 there are no crashes.
    Can this be a Bluetooth problem since N95 uses Bluetooth 2.0 and N6630 an older version?


    Kurt
    Last edited by Kurt Johannes; 2007-12-03 at 18:56.

  4. #4
    Regular Contributor
    Join Date
    Apr 2005
    Posts
    75

    Re: Inquiry scan mode <-> Inquiry mode

    Update:

    It seems that the crashes appear when service searches are performed after an inquiry has finished. It works fine for a couple of minutes (4-7 minutes) but then one phone crashes.
    Without service searches it works fine except the fact that the performance decrease...

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