Cryptic crossword clue
Knack required on check for input device 5,6

The most common and most likely answer to this crossword clue is the 5 plus 6 letter word TOUCH SCREEN

I've seen this crossword clue in The Daily Telegraph
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Buddy explains!

The straight part
We know that "input device" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case input device = touch screen.
The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.
This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.

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