I am using cellphones as virtual extensions. It works as follows: 1) When we get a call the digital receptionist gets the call 2) As caller press let's say #2 they get to extension 002 3) Extension 002 is not registered and forwards the call directly to a cell phone 4) If no one picks up such cell phone in a timely manner the cellphone answering machine picks up I just wish that if we didn't pick up the cell phone in 20 seconds 3CX will notice that the call has not reached a live person and would ask the caller to either leave a message or go back to the main menu. Is this a paid version feature only maybe? I'm I missing any obvious steps in the configuration that would allow me achieve what I'm describing here? Thanks for reading, much bigger thanks for replying, infinite THANKS for offering an easy to understand solution! Kudos to the creators of 3CX!