LG M5520CCBA Owner's Manual page 85

Controlling the Multiple Product
RS-232C
Transmission / Receiving Protocol
47. Serial no.Check (Command : f y)
► To read the serial numbers
Transmission
[f][y][][Set ID][][Data][Cr]
Data FF (to read the serial numbers)
Acknowledgement
[y][][Set ID][][OK/NG][Data1] ~ [Data13] [x]
* The data format is ASCII Code.
A29