Selling a fully depreciated business asset

We have a piece of equipment in our shop that is around 18 years old. Is the cost basis zero since it is fully depreciated? or is the cost basis what we originally paid for it? I don't think we will be selling it for more than what we paid for it, so if there is no "gain" will we still have to report the sale as income? or will there be a way to report it in Turbo Tax where it will automatically be recorded correctly?