There's an option on Skype that lets users call from their computer to an ordinary phone. This means that the call must travel through both the Internet and a telephone network in order to be...

Extracted text: There's an option on Skype that lets users call from their computer to an ordinary phone. This means that the call must travel through both the Internet and a telephone network in order to be completed. Make sure to talk about the specific devices that are involved (e g. router/switch/gateway).