ELI5 : How do phones work while on speaker mode?


How does phones not transmit back what the person on the other side said while speaking on a speaker?

How does phones understand when to transmit and when not to?

In: Technology

They send and receive sound simultaneously. There is, however, a process called “echo cancellation”. A “copy” of what is being sent out to the speaker is phase-inverted and fed back into the microphone circuit. This effectively cancels out the sounds of the speaker that the microphone itself is picking up.