Exact item shown. MISUMI EXRS-H1 teach pendant. with the cable cut near the strain relief.

I couldn't resist seeing if this was working, and lo and behold, it actually is (see second photo). To figure this out, I opened the case and traced out the circuitry, identified the power wires (orange positive, yellow return), and brought the voltage up slowly using my bench power supply.

As you can see, it came alive at about 12 volts and complained that it didn't have a host to talk to ("NG COMM error (TIME OUT)"). This is exactly what I expected.

Other photos show internal details that helped me figure out how it works and also show that there is no obvious physical damage to the electronics.