Getting started with Linux, LinuxCNC and CNC

Unfortenatley, I cant see them anywhere. But here are the shematics.

Can you see any current-limiting resistors on the little PCB in the sensor-box?

Are the LEDs wired in series or parallel?

If the measured voltage at the sensor-box end of the 5V wire is less than 5V then that would tend to suggest that there is current limiting in the supply. If it is a full 5V then is sounds like the current limiting is in the sensor-box or in the devices themselves.

I ll measure it, and post the results here so we can see whats going on

Stupido me, I brought it home, and I forgot that I dont have power source here to take any kind of measurements.
Better photos are included, but its not likely that they will be too much help?

You should be able to figure out if the LEDs are wired series or parallel.
If you had a bench PSU you could see what voltage the LEDs take to reach 20mA. That would hint whether the Optos were 5V devices or not.

I ll have to hook it up to the machine to take measurements.
From few days ago, if I recall correctly, a friend tried to do the measuring, and he was getting 5V, and 1.2V. But that doesnt help much...