Where did you get the JIS.DAT? It may be converting from some other codepoint to 852. You can create your own .DAT file using the ZebraNet Bridge font wizard, but it is a manual job to enter the codepoints into the wizard to create the file.
I get it from guy who was setting some Zebra printer up for another customer, but it was a long time ago and he is not sure whether the file is needed at all. I opened it in ZebraNet Bridge and it seems the conversion table is correct, but, and that was my question, both input and output data in the table are 16 bit, whereas our input coding is 8 bit (Czech cp852, old DOS national table) and eg for "Ň" there is no two byte char "0x00D5", there is only single byte "0xD5". Therefore for the JIS.DAT table to be working there must be something, what tells "input coding is 8 bit, do not treat input data as 16bit" to the printer. I tried ^CI0 (and many other numbers) but with no luck. I obviously do not get how the printer handles data conversions.
PS: We have appropriate *FNT fonts in our older Zebras and it works with no problems, but these fonts are not supported by ZT series (as we were told AFTER we have buy it), we must use TTF. Zebra is announcing ZT230 as S4M replacement, thats why we bought the ZT230. Incompatible replacement! Very handy for customers. And very nice when we see listing that internal fonts in ZT230 are still .FNT in font list!