PLMN file (6F30) will contain the PLMN information, PLMN is comprised of Mobile Country Code (MCC) and Mobile Network Code (MNC), the detail can be found in GSM11.11, and the coding of PLMN can be found in GSM 04.08, here give some example,
1, example 1, 246 for the MCC and 81 for the MNC.
the format is as,
¦MCC digit2 ¦ MCC digit 1 ¦ octet 1
+———————–+———————–¦
¦ 1 1 1 1 ¦ ¦
¦ ¦ MCC digit 3 ¦ octet 2
+———————–+———————–¦
¦ ¦ ¦
¦ MNC digit2 ¦ MNC digit 1 ¦ octet 3
so the result is 42F618
2, exampe 2, 123 for MCC and 456 for MNC
if MNC is 3 digits, seems the format in example 1 cannot be used, in this case, you need to refer to 3GPP TS 24.008
¦ MCC digit2 ¦MCC digit 1 ¦ octet 1
+———————–+———————–¦
¦ ¦ ¦
¦MNC digit 3 ¦MCC digit 3 ¦ octet 2
+———————–+———————–¦
¦ ¦ ¦
¦MNC digit2 ¦ MNC digit 1 ¦ octet 3
the result is as 216354
This two examples should cover all the cases.