An IP phone uses Voice over IP technologies allowing telephone calls to be made over an IP network such as the internet instead of the ordinary PSTN system. Calls can traverse the Internet, or a private IP Network such as a that of a company. The phones use protocols such as Session Initiation Protocol, Skinny Client Control Protocol or one of various proprietary protocols such as that used by Skype. IP phones can be simple software-based Softphones or purpose-built hardware devices that appear much like an ordinary telephone or a cordless phone. There also exist the possibility to reuse ordinary PSTN phones as IP phones, with analog telephony adapters (ATA). One of the primary motivations for implementing such a system is the lower calling cost. When calling other IP phones over the internet one only pays for the usually fixed cost internet bandwidth.

It may have many features an analog phone doesn't support, such as e-mail-like IDs for contacts that may be easier to remember than names or phone numbers.

Ter wrote:We have them at work and they are free, thats what prompted me to ask if anyone was using in udon. I have a snom voip phone although it is static when you plug your ethernet lead from it into your router it sets itself up automatically via you ip add. So my thinking is, if i bring one to home plug it into my router i should be able to dial my office for free.
I have one at my dads my sisters ect ect and they all work crystal clear.
Anyway i will try this december and see how i get on.
Ter