Hello.
In FMX640 devices AVL 548 schould be parsed this way:

02 - no of beacons
cc - first Beacon RSSI
06 - first Beacon ID length
7cd9f4174d59 - first Beacon ID
0a - first additional Data length
b708f73403c800ffff71 - first Beacon additional Data
c0 - second Beacon RSSI
06 - second Beacon ID length
7cd9f4155486 - second Beacon ID
02 - second beacon additional data length
806b - second beacon additional data
Regards