Communication is very important to distribution automation (DA) because DA relies on the coordinated effort of various elements in the system. Many communication systems have been designed for DA so far. However, most of these communication systems use proprietary (vendor specific) protocols and are for individual instead of all DA functions. Thus, there has long been a great need for an open and integrated communication system capable of supporting all DA functions transparently. This paper presents a new communication infrastructure, PS-TCP/IP (power system TCP/IP), for all DA communications including customer services. PS-TCP/IP can support all DA functions transparently because it follows three design principles. First, each network element (NE) involved in DA communications, including customer meters, is assigned a unique network-layer address which corresponds to their relative position in the power distribution network. Second, all NEs can communicate with each other as long as they encapsulate their data in a standard-format IP datagram. Third, any ISO layer 1 and 2 protocols can be incorporated easily. PS-TCP/IP's design follows ISO's layered approach. This means that the structure of the communication system is independent of that of any DA function's, thus creating a truly open and transparent communication environment for all DA functions.