I believe that that DTBLNM refers to the terminal table load module name that contains the Translate table that you wish to use. For ISPF this value can be changed by modifying
your options (ispf option 0).ISR3278 is the standard default version (ENGLISH) I have worked at one shop where they used German and they used to specify ISRGE78 so I presume that if you wanted to use Japanese you would have to specify ISRKA78 but this is just a guess.