Quote Originally Posted by Doddy View Post
http://www.t2cnc.hu/downloads/Lichua...r%20Manual.pdf suggests the output is simply the C/E of an optocoupler. Without knowledge of the part number of the opto you could make an educated guess based on common devices - most seem to have a Vceo of 60V upwards.

...of course you could always take one apart to check?
Looking inside I can see a little white (hence likely an opto) 4 pin device adjacent the pins, but like most SMD's it doesn't have the device number, just some cryptic code on it

24V/20ma is a good guess, but there's still the issue of what does it indicate....