NTT DoCoMo Carrier From
Japan

The NTT DoCoMo Carrier From Japan is denoted by codes: 440 10. The followings IDs are called HNI (Home network identity). This code is created by the combination of two other Mobile Country Code (MCC) and Mobile Network Code (MNC). The first three numbers stand for the MCC and they are used in order to identify the region which the carried comes from (in the following example it’s Japan). The last numbers of the HNI code are equal with the MNC and this ID is given for the specific mobile network operator.

Besides NTT DoCoMo Japan has assigned country code + 81. This number + 81 is equal with international calling code and it’s simply the telephone dialing prefixes used for calling NTT DoCoMo numbers.
NTT DoCoMo uses 0 GSM bands, 3 UMTS bands, 6 and 0 CDMA bands.. You can read the specific frequency bands in the table below. All bands of the NTT DoCoMo are display in MHz units.
Another important information in NTT DoCoMo Japan architectures is the standard of used protocols. It also uses 4 protocols such as GSM, UMTS, LTE, CDMA. The ISO standard code of NTT DoCoMo is JP. You can see more info about this mobile network operator at http://www.nttdocomo.co.jp. How to check NTT DoCoMo coverage? How to check if your phone will work in Japan?