Shouldn't have to. Should be able to talk intelligently about what you do and that should be enough. If I write SW that interacts with RFID readers, I should be able to talk about the various protocols. I should be able to talk about poll vs push and the benefits (and pains) of both. I should be able to talk about how to architect a performant system that gets the data from the devices, processes it and sends it on to some other device.

I should not have to worry about not being able to show any of that. If the people interviewing me don't understand what I did without me showing them, then I am certainly applying at the wrong company.