coding doesn't have any bytes in the binary code showing if MNC
should be 2 or 3 bytes. And if you read 3GPP
ii) Mobile Network Code (MNC
) consisting of two or three digits for GSM
applications. The MNC
identifies the home GSM PLMN
of the mobile subscriber. The length of the MNC
(two or three digits) depends on the value of the MCC.
value is dependent on the value of MCC. And this is no problem in the backends where MCC and the corresponding length of MNC
can be maintained in tables. However if some terminal / user equipment reads the IMSI
it's not reasonable to maintain a table. So is this information stored somewhere? Yes the fourth byte of the file EF_AD
maintains this information.
So should you have some problems with APN
populating MMC and MNC
with wrong number of digits after reading IMSI
, then please change the fourth digit in EF_AD to 4.