A method of controlling telephone connections for internet protocol communications provides a structure for encapsulating a message to be exchanged between an IP phone and an entity within an Ethernet-based PBX, comprising utilizing a Protocol Header and an IP Message body, wherein the Protocol Header includes an indication of Protocol Type for denoting whether the message is an IP message or an encapsulated non-IP message, Device Number for denoting, by means of a MAC (Media Access Control), an address for the entity within the PBX to which the message is to be transmitted or from which the message is to be received, and Message Type for identifying the type of message contained in the IP Message Body.