How did people call for prayer in Al-Aqsa Mosque, in the past?
It was a common practice (until the middle of the last century) that the muezzin ascends to the top of the minaret in order to make his voice when calling for prayer reachable to the other regions.
The lead muezzin used to give the other muezzins the signal using a flag, so that they all call for the prayer at the same time. In 1952, the first loudspeaker was installed on Al-Aqsa Mosque’s minarets so there was no longer a need for the muezzin ( who calls for the prayer ) to rise to the minaret and the call for the prayer.