Flash 3, flash 1 are generally instructions for searching for Bluetooth signals of mobile phones. Generally, there are three indications: "Searching", "Signal Found" and "No Signal Found". Which one the specific flash number represents depends on the instruction.
The voice is getting smaller and smaller. First, whether to turn down the bell. Second, whether the access accessory selected when the earphone is connected is correct. Sometimes, this problem is due to the choice of stereo headphones, but in fact, mono Bluetooth headphones are used.