呼叫保持 Call hold ; HOLD ; Call on hold

呼保易 hu baoyi

呼吸保护 Respiratory Protection ; Respirator

呼吸保护器 Respiratory protective devices

呼叫保留 Call Hold

呼吸保护装置 Respiratory protective devices ; respiratory protection equipment

呼损保持 lost calls held

呼叫保密业务 call privacy service

呼叫保持时间 call holding time

层站呼梯信号保护 landing call protection