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