It is narrated from Abdullah bin Umar, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: Bilal gives the call to prayer while a portion of the night remains, so continue eating and drinking until Ibn Umm Maktum gives the call to prayer. Ibn Umm Maktum was a blind man; he would not give the call to prayer until it was said to him, "You have entered the morning, you have entered the morning."
Hadith Referenceمسند الإمام الشافعي / كتاب الصيام / 615
Hadith Takhrijاخرجه البخاري، الاذان، باب اذان الاعمى اذا كان له من يخبره (617) ومسلم، الصيام، باب بيان ان الدخول في الصوم يحصل بطلوع الفجر ..... الخ (1092)۔