voice call sign

例句：

1. 1.The team leader used a voice call sign to notify everyone of the emergency situation.
   团队领导使用语音信号通知大家紧急情况。
2. 2.The pilot used a voice call sign to communicate with the ground control during the flight.
   飞行员在飞行过程中使用语音信号与地面控制进行通信。
3. 3. In order to avoid confusion, each team member must use their own voice call sign.
   为了避免混淆，每个队员必须使用自己的语音信号。