Hisnul Muslim · Dua 24 of 267
What to say upon hearing the Athan (call to prayer)
((يُصَلِّي عَلَى النَّبِيِّ صلى الله عليه وسلم بَعْدَ فَرَاغِهِ مِنْ إِجَابَةِ الْمُؤَذِّنِ)).
English meaning
‘One should then send prayers on the Prophet (sal-Allaahu 'alayhe wa sallam) after answering the call of the mu.adhdhin’.