Azaan and Iqaamah

Difference between Azaan and Iqaamah

Q: Kindly tell me what is the difference between Azaan and Iqaamah? Kindly consider this Hadith "The people mentioned the fire and the bell (they suggested those as signals to indicate the starting of prayers), and by that they mentioned the Jews and the Christians. Then Bilaal was ordered to pronounce Adhan for the prayer by saying its wordings twice, and for the Iqama (the call for the actual standing for the prayers in rows) by saying its wordings once. (Iqama is pronounced when the people are ready for the prayer). Sahi Bukhari Volume 1, Book 11, Number 577 in Azaan we saying words twice but in iqamah we saying words once as mentioned in above hadees. Kindly now tell me your answer as per Quran and Hadees.