What sound is heard when a call is made to/from the Interphone?

When a call is made to or from the Interphone, the sound that is heard is the HI/LO chime. This specific chime is designed to alert flight attendants and crew members that communication is being initiated through the intercom system. The HI/LO chime is distinguishable and serves as a clear indication that a call is active, helping to differentiate it from other sounds on the aircraft.

In the context of aircraft operations, having a reliable and recognizable method of communication is essential for safety and coordination among crew members. The HI/LO chime can quickly grab the attention of cabin crew, ensuring that messages are promptly received and responded to. Therefore, this chime is integral to effective in-flight communication.