# DUPLEX

> [HTML Version](duplexptrini.htm)

**DUPLEX = <option>**

(Windows only, but see final paragraph below) This function enhances duplex printing. _Option_ may be H\{orizontal\} or S\{hort\} for short edge binding, or V\{ertical\} or L\{ong\} for long edge binding. Anything else disables duplex printing. 

DUPLEX is one of the printer ini file commands that has a [GDI Printing Directive Equivalent](gdiprintingdirequiv.md).

Note that although DUPLEX is only supported directly by A-Shell under Windows, you can effectively support a duplex option in Unix by creating multiple versions of your printer init command which include the required lpr command line options in the [DEVICE](device_sp.md)[pq](keyword-types.md) directive.