... or two letters from AA to ZZ, or blank, it stands for enclosure types; YY could be digit from 31-39, it ... , ZZ could be digit form 30 to 600, it stands for size of TV line, and or followed by EX or ... or two letters from AA to ZZ, or blank, it stands for enclosure types; YY could be digit from 31-39, it ... or two letters from AA to ZZ, or blank, it stands for enclosure types; YY could be digit from 31-39, it ...