If the problem dissapears with headsets then it sounds like it is feedback. Maybe someone has the mic gain turned up too high or a speaker is too close to the mike. You'll need to experment but it could be any one of you who has the problem.
Fujitsu Lifebook P727 laptop review
Lightwell software lets you create mobile apps without using code
Best value Mac: Which is the best £1249 Mac to buy
Comment désactiver les programmes qui s'exécutent au démarrage de Windows 10 ?