# How Do Mobile Credit Card Readers Work?



## cyberphonics (Apr 27, 2008)

Hi all. I've been searching the net for an explanation of the technology behind the credit card readers you can plug into the headphone jack of a smartphone or tablet to be able to swipe credit cards and nothing explains how they WORK, just how to USE them. 

I don't know about them, just that everything I've read says, "Just plug it into the headphone jack of any android or ios smartphone or tablet!" So I thought hey, my Kindle Fire has a type of Android OS and a headphone jack and all of the credit card payment processing apps are compatible with it! 

But none of the readers themselves work. When I asked Amazon why, they just said because they don't work on the Fire, which didn't answer my question lol I see they don't work. I want to know *why* they don't work even though it has a headphone jack and has the apps. 

What's the difference between the Fire's headphone jack and the headphone jack of any other device? Is it a hardware issue or a software issue?

So I thought I'd first see if I can learn how mobile credit card readers work in the first place as far as how devices recognize and interact with them and then maybe that would help me understand what the Fire is lacking to be able to do the same thing.

I'm asking here because I guess this is relevant to smart devices. Thanks!


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## JimE (Apr 16, 2009)

There isn't a difference in the jack. The difference is in the IOS the Fire is running.

There are numerous apps for Android phones, and most of them will NOT run on the Fire. The IOS is locked down to prevent it.


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