Copier Lingo: Duplex Copying

Duplex Copying
The ability to automatically copy on both sides of a page. This can be a useful feature, but it tends to be prone to paper jams. If you want duplex copying, equip the copier with a document feeder called a recirculating automatic document feeder (RADF), which can handle two-sided originals.

Copier Lingo: Recirculating Automatic Document Feeder

Recirculating Automatic Document Feeder (RADF)
An automatic document feeder that can flip the original document over to copy its backside. If you only have an automatic document feeder (ADF), you can copy a two-sided document, but the copies will be on two different sheets of paper.