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Posted by Per Hagman on August 12, 2006, 6:19 am
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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/forum/post.asp?method=ReplyQuote&REPLY_ID=359&TOPIC_ID=163&FORUM_ID=3
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