This is something I've seen with wireless/cell/mobile phones that has been helpful. When a user has problems with a call they can dial something like *9* and it flags the call for technicians. It just makes it easier to find in the logs when someone investigates the problem later on. This would be very helpful for when 3CX phone users report call noise or dropped calls. They could dial the dial code and maybe it would insert a line in the logs to make it easier to find the call or just flag the last call. This would make my life a lot easier when dealing with trouble tickets like "I got a call around 1230 that was dropped but don't remember anything else about it."