No. Your computer can be turned off unless you are using a softphone to make and receive calls. If you have a VoIP telephone or if you are using a VoIP adapter with your handset, you don't require to have your computer turned on, but your modem or router need to be turned on and your connection active. You only need your PC to configure your VoIP phone or VoIP adapter. For configuration instructions go to our VoIP setup instructions.