Wireless: BP-300 looses comms on "X", "O", or "ALL" or any combination of those
If the "X", "O", or "ALL" are not TX'ing or RX'ing and show they are registered its possible some one has locked those key sets out.
To double check this particular scenario power off the belt pack. Then simultaneously press and hold the "X", "ALL", and "O" buttons. Hold those buttons down and power on the belt pack. Wait for the POWER ON indication voice over then release the "X", "ALL", and "O" buttons. If that does not resolve it the first try, relax and try the same sequence again.
It might be necessary to clear the base station of all the REGISTERED packs and re register them just to ensure there is a "clean" set up.
If you still are having the same issue, contact Clear-Com tech support