Sounds like the beltpacks are configured for listen only operation.
Power down the BP210 units
From an off state hold down the volume up button and press and release the power button, then release the volume up button. You should hear the prompt indicating that this was done successfully. The unit should now be able to talk and listen
BP210 settings
Power down the BP210 units
From an off state hold down the volume up button and press and release the power button, then release the volume up button. You should hear the prompt indicating that this was done successfully. The unit should now be able to talk and listen
BP210 settings