ES1624n MFP Userís GuideInstalling upgrades ï 88INSTALLING UPGRADESThis section explains how to install optional equipment into yourprinter. This includes:> duplex (two-sided printing) unit;> additional RAM memory;> 20 GB hard disk drive.DUPLEX UNITThe duplex unit adds the function of two-sided printing, using lesspaper and making large documents easier to handle. It also enablesbooklet printing, which uses even less paper and makes largedocuments even easier to handle.The duplex unit slides straight into the rear of the printer andrequires no tools to install.1. Unpack the new unit and remove any transit material from it.2. Switch the printer off. It is not necessary to disconnect theAC power cable.3. Ensure that the unit is the right way up, as shown, and pushit into the slot behind the rear panel. The panel will swinginwards as you push the unit into it. Push the unit all the wayin until it stops and latches home.4. Switch the printer on and wait for it to warm up (about1 minute).