This attribute specifies the E.164 Telephone Country Code (TCC)
for the country in which the network resides. If applicable, it is
specified as 1 to 3 BCD digits.
The 3 BCD digits are stored with the length of the TCC in the low
order nibble, nibble [0] followed by the most significant digit of the
TCC in the next low order nibble, nibble [1], etc.