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RE: [bluetooth-dev] RFCOMM AXIS & DIGIANSWER ?



Hi,

The byte stream 2 1 20 a 0 6 0 43 0 4b ef 2 1 3a ce is an invalid packet.

If you break it down, you can see that:

HCI hdr: 2 1 20 a 0
L2CAP hdr: 6 0 43 0
RFCOMM address: 4b
RFCOMM control ef => UIH
First length byte: 2 => EA bit set to 0 => a second byte will follow, see TS 07.10, ver 6.3.0, page 18.
Second length byte: 1 => total length is 128 + 1 = 129, which is greater than the L2CAP length, which means that the packet is incorrect.

Best Regards

Mats Fridén

Axis Communications

>-----Original Message-----
>From: stolberg@xxxxxxx.se">mailto:stolberg@xxxxxxx.se]
>Sent: Friday, January 19, 2001 5:27 PM
>To: bluetooth-dev@xxxxxxx.com
>Subject: [bluetooth-dev] RFCOMM AXIS & DIGIANSWER ?
>
>
>Has anyone made an rfcomm connection to Digianswer PCCARD 
>running BTSWS 1.07 with the Axis stack? 
>
>We can setup a connection but when we tries to send data from 
>digianswer to axis, we get a crc error. 
>We can send data to Digianswer without any problems and 2 
>Digianswer devices can communicate 
>with each other. 
>
>The problems is that the uih-frame received from Digianswer 
>contains 2 length bytes (ea.bit set to 0) 
>and therefor the crc is miscalculated. 
>If the second length byte is ignored and the first length byte 
>is divided by 2 the length is correct. (Seems 
>to be an general rule). 
>
>The question is: Is this a correct packet that is not 
>supported by Axis or is it just a bug ? 
>
>dump: 
>
>An ':' is sent (0x3a) 
>From digianswer to axis. 
>
>2 1 20 a 0 6 0 43 0 4b ef 2 1 3a ce 
>rfcomm_receive_data:6 bytes, our cid is 65 
>rfcomm_receive_data: Long UIH packet received 
>rfcomm_receive_data: long packet length 129 
>fcs : 181 
>crc_check: CRC check failed 
>
>An ':' is sent (0x3a) 
>From axis to digianswer. 
>2 1 20 9 0 5 0 41 0 49 ef 3 3a 14 
>
>
>
>
>
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