This is the power supply for a VT100 terminal. Galaxy SIII for scale A much better option for providing power to the backplane would be to take a normal PC power supply, add a 24-pin ATX header ...

[Hash] found that the internal switch-mode power supply on the meter backplane was easy enough to back-feed with a 12-volt bench supply, rather than supplying the meter with the full 240-volt AC ...