You can download and install the Z1 and Z2™ Data Viewer here:

Click "Software and Firmware Downloads"

Download Data Viewer by following the prompts.  

Please note that the USB cable is a custom cable, designed for use with the Z1™ and Z2™.  This USB cable must be used or your device will not sync and you will be unable to proceed with Data Viewer download.  The Data Viewer is designed for downloading to a Windows based computer system.