"new" firepods not connecting

I recently acquired 2 additional firepods to go with one I already had,( and that one works great). To test the "new" units I disconnected the working unit and used the cables to connect each "new" unit individually. Neither showed up on the input/output list on the computer (XP that is not online). I plugged the original back in and it was recognized. Any suggestion or advice to get the two new units communicating?

Are they all running the same firmware?

not sure how to check. Can you tell me how?

Have a look at this:

http://support.presonus.com/entries/21744308-Firepod-and-or-FP-10-s-work-as-stand-alone-but-will-not-daisy-chain-