Swipe? Why are these companies (Square included) so backwards in this area? Take a look at iZettle to see how it should be done.
iZettle? Really? Square is much better than that as it is more versatile. You can accept card payment with square at road side, with in cab by just plugging in the reader into your mobile device. And, iZettle expects you to be fully settled inside your shop :-)
Here's a picture of the device I've tried: http://blog.bookingbug.com/wp-content/uploads/2013/02/izettl...