Rescue team communication signals are standardised for breathing apparatus use in belowground mines, including distress, halt, retire, and advance. Signals for communication by rescue team members are specified for rescue trained persons using breathing apparatus in belowground mines. The prescribed code standardises rescue communication and provides that one hoot signifies Distress or Help Wanted, with unanswered calls to be understood as distress; two hoots indicate Halt; three hoots indicate Retire; and four hoots indicate Advance.