The last byte (0xC5) is not a fixed value. It is the 2's complement of 59. In the sample, the "measured power" of the iBeacon is -59dB. Yes, there's no service ID in the message. So [CBCentralManager scanForPeripheralsWithServices:options] in the background won't see the iBeacon, but this doesn't mean that the iPhone doesn't see it when backgrounded. iBeacons support is in CoreLocation; your app can express an interest in location changes when in the background. The flags field is explained in the Bluetooth spec (Core Spec, version 4.0, Volume 3 Part C (Generic Access Profile), section 18.1. hth, Stuart On 10/6/13 12:00 PM, "bluetooth-dev-request@lists.apple.com" <bluetooth-dev-request@lists.apple.com> wrote:

Message: 3 Date: Sun, 06 Oct 2013 09:35:04 -0500 From: Qinghui Tang <tangqinghui@hotmail.com> To: Frederic Visticot <fvisticot@gmail.com>, "bluetooth-dev@lists.apple.com" <bluetooth-dev@lists.apple.com> Subject: RE: Decoding iBeacon BLE message Message-ID: <SNT149-W872359A5B16CA0E3511DA1B6120@phx.gbl> Content-Type: text/plain; charset="iso-8859-1"

the iBeacon is sent through manufacturer option in Advertisement packet. http://stackoverflow.com/questions/18906988/what-is-the-ibeacon-bluetooth- profile 1A Message Length (26 bytes), including 0xFF and all following bytesFF Manufacturer option4C 00 Manufacturer ID (Apple's)02 15 Apple specific, maybe defining the message type as "iBeacon" and it length (0x15 = 21 bytes = 16+4+4+1) E2 C5 6D B5 DF FB 48 D2 B0 60 D0 F5 A7 10 96 E0 (16bytes for UUID) 00 42 (2bytes for major) 00 58 (2bytes for minor) C5 Seems fixed value

From: fvisticot@gmail.com Date: Sun, 6 Oct 2013 10:27:46 +0200 Subject: Decoding iBeacon BLE message To: bluetooth-dev@lists.apple.com

I try to understand the BLE message send by an iBeacon (from Apple sample app) I have installed a BLE sniffer and I get the following message I have tried to decode- Can someone help me to understand the remaining ?

- In addition I do not see any serviceID send in the message: Does it mean that the iBeacon can not be visible when the app is not in foreground ?

02 (length)

01 (GAP_ADTYPE_FLAGS)

1A ?

1A Longueur (message length)

FF 4C 00 02 15 ?

E2 C5 6D B5 DF FB 48 D2 B0 60 D0 F5 A7 10 96 E0 (16bytes for UUID)

00 42 (2bytes for major)

00 58 (2bytes for minor)

C5 (?)

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