From him, from some of our companions, from Isma'il ibn Jabir:
Abu Abdillah عليه السلام, peace be upon him, would give the Adhan while someone else would give the Iqamah, and Imam عليه السلام would give the Iqamah after someone else had given the Adhan.
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 303