It sounds like there is something wrong with your interpretation of your sentence.  Judges are usually not stupid, and I think its unlikely that you would have been ordered to have an interlock system installed in your vehicle during the period of time that your license was suspended.  I think it is more likely that the interlock system was supposed to commence at the point when you began driving again i.e., when your license became unsuspended.  In any event, however, I clearly was not in court with you, so I cannot tell you exactly what the judge or prosecutor said and what you are required to do.  Therefore, I suggest either consulting with the attorney who represented you, or, if you represented yourself, ordering a transcript of the court date when the conditions were imposed.  Another option would be to go to the clerk's office at the court and request a copy of your file.  You should be absolutely certain with respect to the condition that have been imposed on you before you get back behind the wheel.  Failure to remain in compliance could very easily land you in jail, and not having a proper understanding of the conditions placed upon you will NOT constitute a defense.