Automatic order printing

Hi,

My friend has a pizza shop and has asked me to build a website for him. I have searched around and managed to work out how to build an e-commerce website using wordpress but I am still not clear on how the order will automatically be printed in my friends shop? How can I send the order from website to a thermal printer? what is the most economical way to do this? Is there any wordpress plugin that can do this for me? What kind of thermal printer do I need? Also does my friend need internet in his shop or phone line is enough?

thanks a lot