With minimal effort, Grandstream's BudgeTone series of IP phones can make and receive calls on your network—even without a PBX server.
In most enterprise VoIP setups, you have a PBX that connects all of the phones on the network. The PBX acts as a centralized signaling authority and access-control server for all of the telephone users. But some IP phones don't need a PBX at all. They can call each other directly by way of an IP address. You're about to make a direct IP-to-IP call with a BudgeTone hardphone.
A hardphone is an IP phone that isn't a softphone. It looks just like an ordinary business phone, but plugs directly into an Ethernet local area network (LAN).
The Grandstream BudgeTone 100 phone model has a Menu key, an LCD display, and two arrow keys that you use to navigate its configuration menu options: DHCP, IP Address, Subnet Mask, Router Address, DNS Server Address, TFTP Server Address, Codec Selection Order, SIP Server Address, and Firmware Versions (called Code Rel on the phone's screen). When you get to the option you want, you press the Menu key to select it, and then enter the numeric data required for each option using the keypad. Use this menu only to set up the IP address, subnet mask, and router (default gateway) address, because you'll be doing the rest of the phone's configuration using its web interface.
To get the phone enabled for the next configuration step, turn DHCP off and assign an IP ...