This Technical Report concerns the following communications deliverable within M/441: A European standard comprising a software and hardware open architecture for utility meters that supports secure bidirectional communication upstream and downstream through standardized interfaces and data exchange formats and allows advanced information and management and control systems for consumers and service suppliers. The architecture must be scalable to support from the simplest to the most complex applications. Furthermore, the architecture must consider current relevant communications media and be adaptable for future communication media. The communication standard of the open architecture must allow the secure interfacing for data exchanges with the protected metrological block. Since no single standard can cover all aspects for the full application range of smart metering systems, the deliverable takes the form of this Technical Report. The Technical Report is the second document produced by the Smart Metering Co-ordination Group following acceptance of the Mandate 441 (M/441). The first - a response to the mandate - was issued in December 2009 and provided an overview of the current and future standardization activities, considering both the communications and the additional functionalities of smart meters. Once the standardization activity undertaken in response to Mandate M/441 is complete for both the communications and additional functionality aspects, a final report will be produced providing a list of the finalized standards in both these areas.