Nice as it is you might have just bought yourself a brick.
These phones are usually put into an office as part of the VOIP setup, they're not like the Vonage phones with an individual IP that can link to any network, rather they use an internal IP for routing calls through the office exchange (NOT an office PBX).
It might be possible for the software to be updated to allow a fixed IP which you could then use as an individual phone, but you would need to have a contract with one of the companies to assign a number to that IP so you can make/receive calls.
Reading that back it's as clear as mud
