Surface supplied divers are less likely to get lost, as they are initially connected to the surface team by at least an airline, and usually also a lifeline which may be used by the line-attendant to communicate with the diver using line signals. Most 21st century surface supplied divers also have voice communication with the surface team, and this allows constant monitoring of the diver's condition by listening to the breathing sounds. Surface supplied divers are therefore able to indicate distress and need for assistance promptly and effectively in almost all cases, and the simple failure to respond appropriately to communications from the surface is also an effective indication of a problem.