There was no other mu'adhdhin (pronouncer) of the Messenger of Allah (ﷺ) except Bilal.

The narrator then reported the tradition to the same effect.
Sunan Abi Dawud Book 2, Hadith 700
← Previous Hadith The call to the (Friday) prayer was made at the gate of the mosque in front of the Messenger of Allah (ﷺ) when he sat on the pulpit, and of Abu Bakr and 'Umar. The narrator then repeated the same tradition as reported by Yunus.

Sunan Abi Dawud Book 2, Hadith 699 Next Hadith → There was no other mu'adhdhin of the Messenger of Allah (ﷺ). He then narrated the tradition which is incomplete.

Sunan Abi Dawud Book 2, Hadith 701