An IP phone service is one that uses your internet connection instead of traditionally hard wired public telephone service. You get a device that connects to your router or modem and you plug a telephone into it to place and recieve phone calls.
Basically, any device that needs to communicate with another device on an IP network will require an IP address. so, each PC and router will need an address, along with anything else per above: a switch, a server, and IP phone, etc.
An IP scrambler is a device that scrambles your IP address making it nearly untraceable.
A Cisco PBX IP is used as a stackable integration device that emulates a digital or analog phone, and connects over a Local Area Network. This device is only available in the United States, Canada, and Western Europe.
A IP softswitch is a controlling device for connecting/managing telephone calls while an IP PBX is a phone system used for transmitting voice, video and other data over networks like the internet.
Internet phone conforms to Internet protocol. Analog phone can work with digital line by connecting a ATA into it. ATA is a connector or device that will convert analog signal to digital signal making standard phone an IP phone.
Every IP address is unique - there is no single IP covering every mobile phone !
There's no such thing as phone over or under IP. You may mean VoIP.
A unicast message is a message directed to a specific device on a network (just one specific device). It would have a destination IP address that corresponds to that device.
gateway
VoIP phone allows for IP phone use. It stands for voice over internet protocol.
Multi-homed device.