In NJ, once the contract is signed by both parties, the clock starts.
Generally, the contract will go to the attorney for both buyer and seller. One of the attorney generates a letter and the other responds. Once both attorneys agree on the terms of the contracts and the addendums with any changes made by the attorneys, you are considered out of attorney review. It can take hours, days, or even weeks.
However, if either party does not have attorney representation, the contract is considered out of attorney review within the 3 days indicated on the contract.