Olivier, I got one at a local electronics store where they sell the Arduino, Raspberry Pi and other micro controller stuff. I just hooked it up after reading your post; it was on my to do list, I have a Leadshine driver and a servo that only take 5v step, dir, enable.
I got a little adjustable board that takes the 12v from the TinyG fan and gives me a 5v output for the HV side reference of the leveler. You need some 5v source. I used the 3V, ground, step and dir on motor 1 of the TinyG for the LV side. The leveler is clearly labeled for power and data lines; hv gnd and lv gnd power are the middle pins and data are outside pins.
h1,h2 (gnd, hv) h3,h4 and l1,l2 (gnd,lv) l3,l4
so it can take four 3v data lv inputs and output four 5v hv signals. It looks good so far, outputs 5v for the dir and the step pulses drive an LED (dimly) but I have not hooked it up to a scope or the leadshine. I am new to this also and not an electrical engineer, I'm a classical guitarist. :-)
Larry Deack
WeBeCnCn