If you happen to be lucky enough to have a POTS emulator sitting around, you can connect the card up to that and run a real ISDN connection
Alternatively, if you have TWO of these cards, you should be able to connect them directly with a crossover cable. You might even be able to leverage such a system to spin up a software-driven POTS emulator using the ISDN channel (essentially, phone "passthrough" that really just connects to an internal Asterisk server).