Richard,
If we have an "intelligent" field such as telephone number where different components of the field hold meaning then, in order to comply with normalization rules, these should be split into a number of fields, each containing one of the components. A USA telephone number, for instance, becomes AreaCode, Npa, Nxx. Some of these components could then be supported by a LookUp table (such as AreaCodeT for example).
These can then be formatted/concatenated in forms and reports, and we wouldn't need to jump through hoops to discover the hidden "meanings"... Just my $0.02. Good stuff as always, thanks.