Toshiba IP5000-UG-VC Manuale Utente

If you have a headset plugged into the microphone/speaker jack of the PC, you do not 
have to always enable echo canceller. We recommend you to enable echo canceller in 
the event you want to use the PC's embedded microphone/speaker as a speakerphone 
device and not attach a headset to the microphone/speaker jack of the PC. If the PC 
does not have an embedded microphone even if it has embedded speaker, you do not 
have to enable echo canceller because a headset would be plugged into the 
microphone/speaker jack, see figure below. 

To use Echo Canceller, click the Audio Setting of SoftIPT and check the Using Echo 
Canceller box as shown below.