I need help with a question a faculty member is asking.
In VoIP, a Line connects
1.end station to switching device
2.end station to other end stations
3.switching devices to other switching devices
I'm not sure I understand your question fully, however I'll do my best to answer it.
Your VoIP phone is part of a gateway. The gateway converts telephony into packets for transmission. VoIP providers have servers all over, which allows them to connect, for example, London and Los Angeles. A local call (non IP number) can be completed from the receiving end to a local number.