The mobile phone always flashes when it receives text messages.

However, the ringtone in IMY format was added to the SMS, which is generally not supported by domestic machines, so your mobile phone crashed. It's just the bell symbol you saw in the text message. Generally, they send three kinds, crazy flash, crazy shock and black screen. Find a ringtone in IMY format and send it by SMS. As long as it's not Nokia or Motorola, it usually flashes. The phone vibrates the phone's black screen or flashes all the time. This is a mono ringtone of EMS audio-visual short message with IMY format. Only sound vibrates and blinks at different frequencies. If it goes out for a long time, it will become a black screen effect.