Side Tone on Cisco desk phones

Side tone produces a slight echo in the headset so you can hear yourself speak in addition to the caller.

Cisco desk phones have the option of enabling side tone in the headset. This is not available on all models and you should reference the phone manual for the options of your specific model(s).

If this option is enabled (it is set to default on some phones automatically), and you would like to eliminate the echo, you can go into the menu of your phone or Cisco Call Manager and disable it.