Hi Champ065,
If you have the NI-Switch drivers installed, then you can go to the NI-Switches Help. This can be found by clicking Start >> Programs >> National Instruments >> NI-SWITCH >> Documentation >> NI-Switches Help. When you open this up, navigate to NI Switches Help >> Devices >> NI PXI-2501/2503. From there, select your topology and you can see the pinouts on the right.
Please let me know if you have any problems finding this.
Thank You,
Nick F.
Applications Engineer