AT+CPBW=?
Test command returns location range supported by the current storage and
types of address as compound values, the maximum length of <number> field,
supported number formats of the storage, the maximum length of <text> field,
the maximum length of <group>, the maximum length of <secondtext> and the
maximum length of <email>. The format is:
+CPBW: (list of supported <index>s),<nlength>,(list of
supported <type>s),<tlength>, <glength>,<slength>,<elength>
Additional info: