Java APIs

Dear all,
I have developed an online ordering website for a restaurant which currently
sends the order details through fax using a third party library (www.interfax.net).

I am looking for a solution to send the order details to a personal computer located
at the restaurant, then somehow print the order details from a thermal receipt printer.

I am wondering if the personal computer must have a static i.p address in
order to be found on the internet, and of course I assume that the personal
computer must connected to the net (unless there are some other solutions).

This is how far I have come, as I have little knowledge of networking.

If that is the solution then I would appreciate if you could provide me with
some code examples or guides of how to communicate with a remote computer
by its static i.p address.

To clarify, I want to transmit data from a website to a remote PC.

Thanks!