(11) CHAPTER. The witness of a blind man, his marriage, his affairs, the marriage conducted by him, and his buying and selling; and accepting his call for the Salat (prayer), etc., and what can be known by sound or voice.
Narrated `Abdullah bin `Umar: The Prophet said, Bilal pronounces the Adhan when it is still night (before dawn), so eat and drink till the next Adhan is pronounced (or till you hear Ibn Um Maktum's Adhan). Ibn Um Maktum was a blind man who would not pronounce the Adhan till he was told that it was dawn.
Authentic