How much time separates the first and second Adhans for Jumu'ah (Friday prayer)?

The interval between the first and second calls to prayer (adhan) for Friday prayer is the time sufficient for people to prepare and go to the prayer. It was commanded by Uthman ibn Affan, may Allah be pleased with him, to alert people and prepare them. As for the second adhan, it is an announcement of the prayer time's entry when the Imam enters and sits on the minbar, as was the practice during the time of the Prophet, peace and blessings be upon him. The purpose of the first adhan is to alert people to go early, and the purpose of the second adhan is to announce the entry of the prayer time. There must be enough time between the two adhans to achieve the benefit of the first adhan.