Azaan And Takbeer For Congressional Prayer
Azan is to call people for prayer ( it was also used at other times when some important congregation was required other than Salah ) and iqamat is a compulsory call to begin the Salah. It was uswa of the Prophet to offer only Farz Salah in the mosque and he used to offer nafal salah back in his home. Please see for Azan and iqamat : Discussion 53028 Please also watch : https://youtu.be/3gejKNKdT9A