Scan response packet sent by beacon without any scan request

[Jusang Kim]

reco_scan_req.PNG

Now i am doing a test of RECO beacon which use a nordic chipset, nrf51822. But something strange came up to me during the test with Ellisys bluetooth analyzer. The problem is that the RECo beacon sends scan response without any scan request. Please take a look of the highlighted area of the attached picture.

Any comments on this ?

My test configuration are as follows;

1. Wireless Test
2. Office environment : There are many Bluetooth scanner in the same room.
3. RECO beacon : the device address(D8 4E 4E E1 CD F9). I used the iBeacon example code.
4. My smart phone plays a role of scanner with the device address(4A F1 E3 4B A0 C2).
5. I used the software filter only to filter the devices. (D8 4E 4E E1 CD F9 & 4A F1 E3 4B A0 C2)

[Stian Røed Hafskjold]

Since you are filtering on the two devices D84E4EE1CDF9 and 4AF1E34BA0C2, maybe the scan request is not shown in the list if the scan request comes from another scanner that is filtered out?

[Jusang Kim]

Thank you for reply. Yes I do filtered only two interesting devices such as D84E4EE1CDF9 and 4AF1E34BA0C2 . But Please take a look the attached picture. And find out the blue colored area which captured the scan response packet. The scan response is for scanner 4AF1E34BA0C2 as you can see. This is waht i am curious about. Ellisys bluetooth analyzer did not capture the scan request from the scanner 4AF1E34BA0C2 on the attached picture. but how does the Ellisys bluetooth analyzer know that the scan response is for the scanner 4AF1E34BA0C2 ?