DSL was not working

She told me that her internet wasn't working. I asked her if her phone was working. Her reply was that the phone worked fine. As first step I checked if all cables were plugged in. This was the case. Secondly I asked her if she had already reset the modem. Obviously she did not because she asked me how she could reset the modem. So I plugged out the power supply of the modem and plugged it in again in order to reset the modem. Afterwards the internet worked again.