Explanation of an AT Command

AT+CRSM=214,28539,0,0,12,“FFFFFFFFFFFFFFFFFFFFFFFF”

I would like to understand the complete meaning of this AT Command. I am using MC60E module. The AT Command Manual says refer to GSM11.11 but I am not able to find anything there.

Please help me with the following, as I have just begun with this yesterday.

214 (Command): Update Binary
28539 (Fileld): This is the identifier for an elementary data file on (U)SIM
,, Integer type. Parameters passed on by the ME to the (U)SIM.
0 (P1): (Offset High)
0 (P2): (Offset Low)
12 (P3): (Length)
Information which shall be written to the (U)SIM (hexadecimal character format)
FFFFFFFFFFFFFFFFFFFFFFFF (data):

Please somebody help me with the FFFFFFFFFFFFFFFFFFFFFFFF

To understand AT+CRSM you can look at documents e.g. TS 27.007
For the parameters you look at GSM 11.11 or TS 51.011, etc

28539 (6F7B in hex) => Forbidden PLMN
The “FF … FF” are values to be written to SIM

The SIM holds 12 bytes of forbidden PLMN list. The above command will clear the list on the SIM by filling with “FF”.

Thank you so much for your help.