Pulling 5v from I-PAC to Opti-PAC

[DemonBrew]

RTFM, I know know. But I'm still unsure. The search on this forum also doesn't turn up the answer I'm looking for.

 From Ultimarc's site:

Do I need a power supply?
Not if you use in USB mode.
In serial mode the board does need a 5 volt supply. A cable is supplied which plugs into the I-PAC board if you have one, to provide this supply. If you are not using an I-PAC board, a 5 volt supply can be obtained from a joystick port, ps/2 mouse port, or any other 5 volt source from the PC.

I am running a single Ultimarc trackball on the Opti-PAC. Got that wired, no prob. However, not sure how to grab the 5v from the I-PAC over the Opti-Pac (since I am using the serial connection). The Opti-PAC came with wires / harness to do this. I don't have it in front of me - but is it just black to GND on I-PAC and red to any unused SW on the I-PAC?

[Tiger-Heli]

No it's black to either GND on the I-PAC or the header pin and red to the appropriate header pin as shown here http://www.ultimarc.com/ipac2.html under "Header Plug and LED wiring diagram."

[DemonBrew]

That's what I was looking for, thanks!