Contact array in a card reader

1. A card reader, comprising:

a frame having a slot for insertion of a financial transaction card, the financial transaction card having a plurality of card contacts to communicate with an integrated circuit embedded in the financial transaction card, wherein the slot has open sides that allow the financial transaction card to move laterally during the insertion;

a plurality of reader contacts coupled to the frame and positioned in the slot in a position to be contacted by the card contacts when the financial transaction card is inserted in the slot; and

circuitry configured to communicate with the integrated circuit embedded in the financial transaction card through the plurality of card contacts, wherein there are more reader contacts than card contacts and the circuitry is configured to determine which subset of the reader contacts engages the card contacts and to communicate with the financial transaction card through the subset of reader contacts.

2. The card reader of claim 1 , where density of the plurality of reader contacts on the frame is twice as high as density of the plurality of card contacts.

3. The card reader of claim 1 , where the subset of contacts are positioned to engage with the plurality of card contacts when the insertion of the financial transaction card reaches a bottom edge of the card reader.

4. The card reader of claim 1 , further comprising an audio jack comprising circuitry configured to communicate with a mobile device.

5. The card reader of claim 1 , further comprising circuitry configured to communicate with magnetic stripe cards.

6. The card reader of claim 1 , where the frame comprises a transparent panel that overlays at least a portion of the plurality of reader contacts.

7. The card reader of claim 1 , further comprising circuitry that displays an indication when the subset of reader contacts is selected.

8. The card reader of claim 1 , further comprising circuitry that outputs an audio signal when the subset of reader contacts is selected.

9. The card reader of claim 1 , where the circuitry is configured to perform operations comprising:

applying, for one or more reader contacts in the plurality of reader contacts, power to the respective contact;

measuring, for the one or more reader contacts, whether power is being drawn from the respective contact; and

selecting the subset of reader contacts based on whether power is drawn from the one or more reader contacts.

10. A method of reading a chip card using a card reader, comprising:

applying, for one or more reader contacts in a plurality of reader contacts, power to the respective contact;

measuring, for the one or more reader contacts, whether power is being drawn from the respective contact; and

selecting a subset of reader contacts based on whether power is drawn from the one or more reader contacts.

11. The method of claim 10 , where applying the power at the respective contact further comprises testing protocol responses at the respective contact.

12. The method of claim 11 , further comprising:

determining whether the protocol responses conform to a technical specification; and

selecting the subset of reader contacts based on the protocol response.

13. The method of claim 10 , where the power is consecutively applied at each reader contact until power is drawn from a particular reader contact.

14. The method of claim 10 , where each reader contact is associated with a respective position, selecting the subset of reader contacts comprises:

determining power is being drawn from a first reader contact;

determining a plurality of positions based on a position of the first reader contact and a technical specification;

selecting the subset of reader contacts based on the plurality of positions.

15. The method of claim 14 , where the technical specification conforms to the Europay, Mastercard, Visa Protocol.

16. A card reader, comprising:

a frame having a slot for insertion of a chip card that has a plurality of card contacts, wherein the slot has open sides that allow the chip card to move laterally during the insertion;

a plurality of reader contacts coupled to the frame and positioned in the slot in a position to be contacted by the card contacts when the chip card is inserted in the slot, and

circuitry configured to:

communicate with the chip card through the plurality of card contact, wherein there are more reader contacts than card contacts;

determine which subset of the reader contacts engages the card contacts and to communicate with the chip card through the subset of reader contacts;

apply, for one or more reader contacts in the plurality of reader contacts, power to the respective contact;

measure, for the one or more reader contacts, whether power is being drawn from the respective contact; and

select the subset of reader contacts based on whether power is drawn from the one or more reader contacts.