Retrofit cnc 3axis

I couldn't wait for the holds to arrive. xD
I opened the db25 to test the pins with the machine enabled. The blue cable in the photo corresponds to ground pin # 13, like the pinout that was in the diagram. I have tried the other pins but they have values ​​between 2.2 and 2.8V which vary to 4V (ACTIVE HIGH) when I enable ANY tool change function, or x y z movement.
For example if I jog on x axis with pin 5 or pin 8,9 I have the same positive variation of Volt. Same thing if I open the tool magazine or jog on y.
Some pins instead remain at 0 without changing during one of the dir or tool change functions.
How can I understand the single pin? I enclose the cable

I tried with the ground on the cabinet and pin13 which is a different color than the rest of the wires. The variation can detect it but the pins appear to be connected as if they were sharing current. Anyway remedy 5v industrial power supply where I can connect the cables. The db25 disconnected from the pc, ground on pin 13 and the other end on one pin at a time, until I find the AXIS ON pin that enables me to control the machine. Not being able to use the control software, when the pin has power will I hear the machine unlock the axes while I press the button to enable it on?

Is the power supply in the photo okay?

Thanks Aciera !!

I'm making the connections on the alligator clips so I can test everything better. Tomorrow I will also receive the power supply to try to activate the pins without a PC.
To connect these sockets in order to act as an extension between the machine cable and the PC: do I have to connect pin 1 of the socket on the left with pin 1 of the one on the right? The 2 with 2, 3 with 3 and continuing up to 25. Finally I have to ground the two cables with the additional GND pin. So then I can measure them directly from above the screw. It's correct?

Great, thanks Aciera.

I have carried out the tests with the adapter, it seems to be clearer with the pc disconnected but I check active, which are the necessary pins, even if I cannot identify them individually.What if I try to plug in a breakout card and go to trial and error?I doubt that the pc communicates with the control board for ability machine.. There is a floppy disk that enables control connected to an internal motherboard. It allows you to draw while the machine simultaneously processes an ISO. If I unplug the floppy and motherboard, can't I replace it with a linuxcnc control card, thus only using the dumb cards (no processors) from the machine?I am attaching photos of the machine and cards and the test.

I'm sorry tommy I can't decrypt well, I understood that the one under input output is the drives card, I noticed the motherboard in the machine cabinet, now it processes the iso data from the external pc where the software resides. Could it be used as a single pc, putting linuxcnc on compact flash and using the old parallel port now unused? Could you suggest me how to do it? If I connect the monitor and keyboard to that card it won't access the bios ...Thanks