Plustek OPTICPRO 12000P TURBO User Manual page 13

Note: Your printer no longer plugs directly into your computer. Instead, it
plugs into the pass-through port on the scanner which plugs into the
computer. This is called a daisy-chain. Your printer and scanner will now
share the same port and the same cabling. Because of this, you will not be
able to scan and print simultaneously. Your computer will wait for any
scanning processes to be finished before it begins printing and vice-versa.
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