You should be able to, but if possible you should set up a way to have a card with a PIN number rather than a signature. The signatures are extra time and hassle, thats not how its normally done there!
I'm assuming you're in the States? If your card has a chip it likely has pin technology built in - I just went on my bank's website and requested to have my credit card pin number mailed to me. I do believe it needs to be mailed for security purposes, I don't think they can tell you over the phone or email.