For example, the ISD series of voice chips, some chips with MIC interface, connected to the electret microphone, press the recording key, the sound is recorded in, and the record is full or all of the stop.
There is also an external voice memory, which can be used to input the sound with the chip, or the sound data can be stored in advance through the external MCU, and then the chip can be played according to the set address information.
There are also voice chips that are not erasable, and those sounds are recorded by the manufacturer according to the user's requirements.