I am new to Raspberry Pi and I want to use an HID Omnikey 5421 with a Raspberry Pi - it is a dual interface contact and contactless reader. After some research I was able to communicate with the contact reader using this post, but the contactless reader is not visible in Raspberry Pi. It seems like some driver problem. Can any one help me with this?
Buy A Compatible Card Reader
You're probably going to have to buy a card reader that is compatible with the Raspberry Pi.
Elaborating on Dmitry's Comment
So you'll need drivers for Linux ARM6 or Linux ARM7.
The only drivers available for ARM6 or ARM7 are for the Windows CE OS:
OMNIKEY 5x2x PC/SC driver for Windows CE
...for Windows CE.NET 7.0 for ARM5, ARM6, ARM7...
I have also been struggling with this same issue, and had a stroke of good fortune with timing!
HID have now released a driver for their Omnikey encoders that is compatible with the ARM processor, and is available here.