Automatic telephone switch: Listen & Download Automatic telephone switch .mp3 Error! Change your browser, please! ⇓ Download Small centrifuge ⚠ Letter press ⚠ Compressor industry ⚠ Postal sorting line ⚠ Spinning machine ⚠ Hydraulic pump ⚠ Grind metal on a grinding machine in a ⚠ Low frequency running engine ⚠ Power station turbine ⚠ Oil pump ⚠ Welding, hammer knocking, Car factory ⚠ Air blow, Air compressor ⚠ ★★★★★