Do you know what these things are?
VoIP is voice over internet protocol, basically a phone call. So there was a phone call or some other call that used VoIP protocol. Ringtone is a prelude to a phone call. If you look at the times it ringtones come before the call, followed by the call.
Just looking at this log they appear to be in sequence. The device rings or alerts, connects to the internet providing the incoming call, followed by the call itself. There on 7/20 at 9:51, it looks like that call didn't take place over an internet connection, so no VoIP protocol.
This app is designed to tell you what is causing your device to ring or vibrate according to the app description. It seems to also record the activity around these...