iBeacon packet structure

After 9 bytes of constant preamble, the Proximity UUID, Major and Minor values are transmitted.

UUID is 16 bytes long, Major and Minor are 2 bytes long. Together they form an ID for your iBeacon. Mobile devices recognize which Beacon they approach on the basis of these values.

Byte offset Default value Description Properties
0 0x02 Data length – 2 bytes constant preamble
1 0x01 Data type – flags constant preamble
2 0x06 LE and BR/EDR flag constant preamble
3 0x1a Data length – 26 bytes constant preamble
4 0xff Data type - manufacturer specific data constant preamble
5 0x4c Manufacturer data constant preamble
6 0x00 Manufacturer data constant preamble
7 0x02 Manufacturer data constant preamble
8 0x15 Manufacturer data constant preamble
9 0xb5 Proximity UUID 1st byte set user UUID
10 0xb1 Proximity UUID 2nd byte set user UUID
11 0x82 Proximity UUID 3rd byte set user UUID
12 0xc7 Proximity UUID 4th byte set user UUID
13 0xea Proximity UUID 5th byte set user UUID
14 0xb1 Proximity UUID 6th byte set user UUID
15 0x49 Proximity UUID 7th byte set user UUID
16 0x88 Proximity UUID 8th byte set user UUID
17 0xaa Proximity UUID 9th byte set user UUID
18 0x99 Proximity UUID 10th byte set user UUID
19 0xb5 Proximity UUID 11th byte set user UUID
20 0xc1 Proximity UUID 12th byte set user UUID
21 0x51 Proximity UUID 13th byte set user UUID
22 0x70 Proximity UUID 14th byte set user UUID
23 0x08 Proximity UUID 15th byte set user UUID
24 0xd9 Proximity UUID 16th byte set user UUID
25 xx* Major 1st byte set major value
26 xx* Major 2nd byte set major value
27 xx* Minor 1st byte set minor value
28 xx* Minor 2nd byte set minor value
29 0xc6 Signal power (calibrated RSSI@1m) signal power value