I posted the following in reply to your thread on CNCZone. I will repeat here,
Section B3 of the Hitachi manual shows pins 5 and 6 of the RJ45 are data pos and neg
These will correspond to T+ and T- on the RS485 converter. Use one twisted pair in the cat 5 cable
That is all. Only two wires.
Re page B5 of the manual set the following,
A001 03
Aoo2 03
C070 03
C071 05 (this is what I used, other options are available)
C072 1
C074 00
C075 1
C076 02
C077 0.50
C078 10
The last two numbers I have no idea about but these numbers are working for me.
Set the dip switch shown on page B4 to 485
Greg