<phone-number>=<countrycode>(<area>) <exchange>-<line><ext>
# values may be left empty
<countrycode>=
<countrycode>=+1
<area>=<digit><digit><digit>
<exchange>=<digit><digit><digit>
<line>=<digit><digit><digit><digit>
# values may be repeated to increase the frequency of occurrence
<ext>=
<ext>=
<ext>=
<ext>=
<ext>=
<ext>=
<ext>=
<ext>=
<ext>=
<ext>=
<ext>=, ext. <digit><digit>
<digit>=0
<digit>=1
<digit>=2
<digit>=3
<digit>=4
<digit>=5
<digit>=6
<digit>=7
<digit>=8
<digit>=9