With the introduction of PCS1900 with the regulatory mandate to allocate 3-digit MNC codes, additional functionality is required to identify the HPLMN. Assumptions An MNC code shall consist of 2 or 3 decimal digits. In NA PCS1900, all SIMs shall store 3 digit MNCs. Any network using a 2 digit MNC code shall broadcast the hexadecimal code "F" in place of the 3rd digit. For PCS1900 for North America, regulations mandate that a 3-digit MNC shall be used; however during a transition period, a 2 digit MNC may be broadcast by the Network and, in this case, the 3rd digit of the SIM is stored as 0 (this is the 0 suffix rule). With the exception of North America during the transition period:

1. Within a single country (or area identified by a MCC) all networks shall broadcast a 2 digit MNC code, or all networks shall broadcast a 3 digit MNC code. A mixture of broadcast 2 and 3 digit MNC codes is not permitted within a single country (or area identified by a MCC).
2. A network which broadcasts a 2 digit MNC code, will issue SIMs with a 2 digit MNC code in the IMSI on the SIM. A network which broadcasts a 3 digit MNC code, will issue SIMs with a 3 digit MNC code in the IMSI on the SIM.

Definitions and abbreviations HPLMN Matching Criteria in mobiles which don't support PCS1900 for NA Figure A.1 illustrates the logic flow described below. The text below is normative. Figure A.1 is informative.

1. The MS shall compare using all 3 digits of the SIM-MCC with the BCCH-MCC. If the values do not match, then the HPLMN match fails.
2. The MS shall read the 3rd digit of the BCCH-MNC. If the 3rd digit is Hex F, then proceed to step (4).
3. The MS shall compare using all 3 digits of the SIM-MNC with the BCCH-MNC. If the values match, then the HPLMN match succeeds, otherwise the HPLMN match fails.
4. The MS shall compare using just the 1st 2 digits the SIM-MNC with the BCCH-MNC. If the values match, then the HPLMN match succeeds, otherwise the HPLMN match fails.

If the EHPLMN list is present and is empty or if the EHPLMN list is not present, the matching procedure shall be done for the MCC/MNC of the IMSI. If the EHPLMN list is present and is not empty, the matching procedure shall be done for all entries in the EHPLMN list until a match is found or all matches fail.

HPLMN Matching Criteria for mobiles which support PCS1900 for NA Figure A.2 illustrates the logic flow described below. The text below is normative. Figure A.2 is informative.

1. The MS shall compare using all 3 digits the SIM-MCC with the BCCH-MCC. If the values do not match, then the HPLMN match fails.
2. The MS shall read the 3rd digit of the BCCH-MNC. If the 3rd digit is Hex F, then proceed to step (4).
3. The MS shall compare using all 3 digits the SIM-MNC with the BCCH-MNC. If the values match, then the HPLMN match succeeds, otherwise the HPLMN match fails.
4. The MS shall determine if the BCCH-MCC lies in the range 310-316 (i.e., whether this network is a PCS1900 for NA network). If the BCCH-MCC lies outside the range 310-316, then proceed to step (6).
5. The MS shall compare the 3rd digit of the SIM-MNC with '0'. If the 3rd digit is not '0' then the HPLMN match fails.
6. The MS shall compare using just the 1st 2 digits of the SIM-MNC with the BCCH-MNC. If the values match, then the HPLMN match succeeds, otherwise the HPLMN match fails.

If the EHPLMN list is present and is empty or if the EHPLMN list is not present, the matching procedure shall be done for the MCC/MNC of the IMSI. If the EHPLMN list is present and is not empty, the matching procedure shall be done for all entries in the EHPLMN list until a match is found or all matches fail. Guidance for Networks in PCS1900 for NA There may be some problems in the transition period from broadcasting 2 MNC digits to broadcasting 3 MNC digits. Here are some guidelines to avoid these problems.

1. Existing network codes. Operators who currently use a 2 digit BCCH-MNC xy should use the new code xy0.
2. New operators allocated 3 digit MNC codes with the same 1st 2 digits as an existing operator shall not use a 3rd digit of 0.

While an MS is roaming on a VPLMN, the VPLMN and a PLMN are of the same country only if their MCC values identify the same country. See clause 1.2 for the definition of country.