Electronic – the ROF pin on the power supply

power supplyswitch-mode-power-supply

I laid my hands on a old power supply (Cisco ADP-29DB CC:B1/1, it came with an Cisco ISDN router many moons ago) and it has a connector with the following pinout:

\text{-12V / 100mA}&*&*&\text{-24V / 120mA}\\
\text{+12V / 100mA}&*&*&\text{-71V / 120mA}\\
\text{ROF}&.&*&\text{+5V / 120mA}\\

Most pins are clear, I guess 'RTN' is simply short for 'return' or GND. Which leaves one pin with an unclear marking:

What does ROF mean? An interesting detail is that the pin for ROF is a bit deeper down into the connector so it makes contact last of all pins, implying that is has something to do with hot-plugging the PSU.

Best Answer

ROF stands for Remote On/Off. This pin must be grounded for the supply to work.