According to AltBeacon docs:
m - matching byte sequence for this beacon type to parse (exactly one
required)
s - ServiceUuid for this beacon type to parse (optional, only for
Gatt-based beacons)
i - identifier (at least one required, multiple allowed)
p - power calibration field (exactly one required)
d - data field (optional, multiple allowed)
x - extra layout. Signifies that the layout is secondary to a primary
layout with the same matching byte sequence (or ServiceUuid). Extra
layouts do not require power or identifier fields and create Beacon
objects without identifiers.
Example of a parser string for AltBeacon:
"m:2-3=beac,i:4-19,i:20-21,i:22-23,p:24-24,d:25-25"
This signifies that the beacon type will be decoded when an
advertisement is found with 0xbeac in bytes 2-3, and a three-part
identifier will be pulled out of bytes 4-19, bytes 20-21 and bytes
22-23, respectively. A signed power calibration value will be pulled
out of byte 24, and a data field will be pulled out of byte 25.
here is a list of some beacon layouts
ALTBEACON m:2-3=beac,i:4-19,i:20-21,i:22-23,p:24-24,d:25-25
EDDYSTONE TLM x,s:0-1=feaa,m:2-2=20,d:3-3,d:4-5,d:6-7,d:8-11,d:12-15
EDDYSTONE UID s:0-1=feaa,m:2-2=00,p:3-3:-41,i:4-13,i:14-19
EDDYSTONE URL s:0-1=feaa,m:2-2=10,p:3-3:-41,i:4-20v
IBEACON m:2-3=0215,i:4-19,i:20-21,i:22-23,p:24-24