I use the speaker phone function of my phone almost everyday for meetings and making personal calls (I often clean my room while I’m talking to my family and friends). When I looked into the design it was as simple as the microphone and loudspeaker being placed separately in the handset. The loudspeaker broadcasts the voices of those on the other end of the telephone line, while the microphone captures all voices of those using the speakerphone. It was created in the 1930s and now it’s as easy as a push of a button.