What does "external public address equipment" mean?

The outside is relative to the inside, and the audio needs to be amplified so that people can hear the sound through the vibration of the speaker. For example, some audio equipment, such as Bluetooth, can hear music directly because of the built-in power amplifier, but in some cases, in order to hear louder sound, it is necessary to use an external power amplifier, such as a power amplifier, and then connect a high-power speaker to hear louder sound. However, some devices can only play sound through the external amplifier, such as many mp3 players and computer mainframes, and can only hear sound through the external amplifier, and can be connected with a power amplifier or an active speaker (speaker with integrated amplification function). Nowadays, many speakers are integrated with amplification equipment, and there is no need to connect external speakers. Whether it is external depends mainly on whether there are audio input and output terminals or wiring. If there is wiring, it can be considered as external public address equipment. Thank you.