When does the EMG button on the Interphone illuminate amber?

The EMG button on the Interphone illuminates amber specifically when the Flight Deck initiates an emergency call. This visual signal is crucial for flight attendants, as it alerts them to an urgent situation requiring immediate attention. During an emergency call, the amber light serves as a warning that the crew must prioritize communication regarding potential threats or safety procedures.

Normal calls, delays, or passenger boarding do not trigger the EMG alert because these situations do not indicate a high-priority emergency. The specific function of the EMG button and its visual indicators is vital for maintaining situational awareness and ensuring the safety and efficiency of the cabin crew's response to emergency situations.