An alcohol interlock device is a breathalyser which is wired into your car's ignition which records every start, stop, test result, violation, km's driven etc which is then available as a report for authorities to view.
Before you start your vehicle you will need to provide an alcohol free breath sample. Once you have passed the test you can then start your vehicle. While you are driving your interlock will call for random tests which must be taken, otherwise this is classed as a violation.
Each month you need to take your vehicle back to a service centre to get the data downloaded and the interlock calibrated, this takes about 15 minutes.