How do you print receipts from cash register machines?

here there are a lot of cash register machine users, they print daily reports/z-reports/ and monthly report or summary reports from being on their office.
if they are out of office they cannot print the receipts. now i am looking a solution for this. i want to make any one who is out of office could print recipts from his own cash register machine. each cash register machine has their own unique codes. and they have network port. so how can i do that? i want to develop a solutions by developing web based application, so that any one can access the site then login using his own username and password.. the can print. so how can i do that.. how to access the cash register machines?
if any one who is intersted in doing this project please let's discuss in email so that we can deal the price of it?
thanks