Duplex may refer to any of the following:
1. Duplex is a term used to indicates that a communications channel is capable of carrying signals in both directions.
2. Duplex printing is a feature on some computer printers that allows them to print on both sides of the paper. They are useful in printing jobs such as the corresponding pages found in a book or magazine.
3. With RAID, duplexing is mirroring across two RAID cards.