If you look at the comments, a commenter further explains the role of each person:
Squad Sergeant: Squad Sergeant
Cannon Conductor: gives the order to fire to each cannon
Time Keeper: Makes sure each shot is fired 5 seconds apart
Shot Keeper: Counts each shot fired from 1-21, Notifies "Final Round" when counter is on 20
Radioman: Wears radio under jacket with earpiece, There is another radioman closer to the event / Funeral etc with another radio and earpiece and will notify the other to prepare and fire the first shot
Found this video on youtube which strengthens this observation even more.
https://www.youtube.com/watch?v=gyzCnL7lvrQ
If you look at the comments, a commenter further explains the role of each person:
Squad Sergeant: Squad Sergeant
Cannon Conductor: gives the order to fire to each cannon
Time Keeper: Makes sure each shot is fired 5 seconds apart
Shot Keeper: Counts each shot fired from 1-21, Notifies "Final Round" when counter is on 20
Radioman: Wears radio under jacket with earpiece, There is another radioman closer to the event / Funeral etc with another radio and earpiece and will notify the other to prepare and fire the first shot