It is narrated from Sayyiduna Abu Juhayfah (may Allah be pleased with him) that Sayyiduna Bilal (may Allah be pleased with him) gave the adhan for the Messenger of Allah (peace and blessings be upon him) at Mina in pairs, and also said the iqamah in pairs.
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18466