The Prophet ﷺ said, "Bilal calls the adhan at night, so eat and drink until you hear the adhan of Ibn Umm Maktum."
أخبرنا قتيبة قال حدثنا الليث عن ابن شهاب
أن النبي ﷺ قال إن بلالا يؤذن بليل فكلوا واشربوا حتى تسمعوا تأذين ابن أم مكتوم
Reported by Muslim, Fasting, chapter on the fact that the beginning of the fast occurs at the break of Fajr, etc., no. 36/1092, from Qutayba, and by Bukhari, Adhan, chapter on the adhan of a blind man when he has someone to inform him, no. 617, from the hadith of Ibn Shihab through this chain, and it is in Kubra, no. 1602.