Does iATS Payment SWIPE work?
We know that the SWIPE processor has been working for some time (at least a couple of years), but we don't have as many live installs using 4.7 or Wordpress, so do let us know how it works out. We have no reason to believe it won't work.

The key functionality of a card reader, aside from reading the card number off of the card's stripe, is to encrypt it, so your card reader would have to be compatible with one of the two expected encryption methods, which you can review at the function iatsSetCreditCardNumber in the js/swipe.js file. If you have one that isn't currently listed but works, then do let us know so we can update the documentation.

And finally - an unrelated word of warning that there are still some issues with contributions in the core CiviCRM 4.7 code. In general, most of the payment functionality is working well, but for example there was a regression in the latest release related to line items (it's not specific to iATS Payments).