Mobile Credit Card Swiper - Informations

I'm in the process of building a mobile POS System. Before starting to build this application, I'm doing some research on the hardware needs of the project. The most important hardware need is the mini Mobile Credit card Swiper like Square Reader: [login to view URL] and Paypal Reader: [login to view URL] For now, I'm just looking for someone who knows how and where to build the custom Cr. Card Swiper. You don't have to build it, you just need research and supply information regarding this. I'm sure there are several companies in China who builds these kinds of product, but I don't know how to connect with them. And it will be great if you can also let me know the technologies behind it, like how to connect mobile application checkout page with the Cr. Card Swiper. Since this project is only about research and information, the budget is very low. But, later on if you want to work on building this application, then I'll be happy to talk about my project details and total cost.