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MS Bluetooth stack causes data transfer delays?

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perhagman

perhagman

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Stockholm, August 12th 2006.

Dear Forum:

In searching for an answer why the transfer of data over a SPP bluetooth link from a scanner to a Smartphone (OS=MS Smartphone 2003) I came across the below forum entry, which I would like to ask you to comment on.

We have a C++ application running on the Qtek's developed in Visual Studio, using the scanner manufacturer's driver libraries, and many times we experience a difficulty already in the pairing of the two devices.

Secondly, the data transfer (a barcode of a few bytes) between these two devices seems to persistently take seconds, whereas the upload and subsequent ascii-code reply over GPRS from the server to display the validated data is much quicker once that data channel is up.

Where do we start the troubleshooting, and what can you perhaps say re. the BT stack problem here below? Probably the "timeout" it speaks of should really be referred to by some other term, no?

Looking forward to your analysis, AND please alert me by email of any blog/forum response!

Brgds,
/Per Hagman

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"I was not sure if the slowing part was the phone or the "Bluetooth to RS232" dongle.

So I wrote a test application that sends a char over ther serial port and measure the time it takes to get a echo response.

When I use a serial cable between PC and my Qtek 8080 (HTC) I got 10 ms in response time. Thats OK.

So changed to bluetooth connection.

The response time was now 1002 ms!!

I removed the "Bluetooth to RS232" dongle and connected a TECOM "Bluetooth to USB" dongle at the PC side. The TECOM use WIDCOMM 1.4210 bluetooth stack.

The responce this time was 1003 ms.

The Qtek 8080 (HTC Voyager) has microsoft bluetooth stack inside.

A conclusion of this is that the microsoft bluetooth stack has some kind of timeout that is set to 1000 ms.

It takes some time to pack/unpack data on the bluetooth link, but it should not take 1000 ms to do this.

Wonder if there is some way to change this timeout?? [?]

Honken"

URL= http://franson.com/f...R...&FORUM_ID=3

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