I got this from my deceased Dell Laptop, PCMCA 56K Modem + Fax. I think this card can be used as ISDN modem but need to buy the interface, I may be wrong since I lost the manual. Bought from DELL around $250-300 (can't remember exactly) just name your price if I feel right I may let it go rather than collecting dust in my drawer. But I will keep it if the offering price is NOT right......