VOIP: Voice Over IP, Router is an access point for the customer or user to access either LAN or WAN, LAN: Local Access Network, and WAN: Wireless Access Network, IP Address is something that should never be given out because that is important to keep for you to access the Router settings with a password that was either set by yourself or someone else who is more tech "Savy". IP Config is a configuration setting inside the computer that you will be able to see the IPv4, IPv6, subnet mask or the default gateway, the reason i know all of this information, I worked with the IT director at my highschool and he helped me learn more about electronics and how computer work and how the possibility of getting into this field i would be able to get more experience and have a great career in this field. A phone switch is used by the enterprises or the public switched telephone network. And finally your last question, a Modem..... That gives you the access to the internet connection. the Modem has a CAT5 cable that goes from the back of the Modem to the back of the router... That is what i know and i hope this helped you as much as i think it did.