PowerEdge 800 power supply pin out...

We really are having a time with this and any help is appreciated.

We have a PowerEdge 800 server that has been running fine for years.  Recently the fan in the power supply is getting a bit noisy.  So we decided to replace the power supply.  The current power supply is the DELL NPS-4200ABA an we notice the pin-outs on the "ATX" 24 pin connector on it are different than the standard ATX connectors.

So we are trying to find the definitive pin-outs for the DELL NPS-4200ABA before we install the standard power supply.

At this time it the only differences seem to be:

ATX - Standard

• pin 9 - purple - +5VDC standby power (always on)
• pin 20 - No connection

DELL NPS-4200ABA

• pin 9 - No connection
• pin 20 - purple - BUT is this +5VDC or +3.3VDC?

So our questions are:

1. What voltage is on pin 20 on the DELL?  +5VDC or +3.3VDC?
2. Are all the other pins the same as the ATX standard? 
3. (an/or) can you provide us with the "official" pin-outs for thisDELL connector?

There are lots of descriptions of the pin outs for desktop but most seem to be 20 pin connector differences and the color codes do not seem to match. 

Thanks in advance for your quick response, we appreciate it.