IEC 62056-3-1:2013 describes three profiles for local bus data exchange with stations either energized or not. For non-energized stations, the bus supplies energy for data exchange. Three different profiles are supported: - base profile; - profile with DLMS; - profile with DLMS/COSEM. The three profiles use the same physical layer and they are fully compatible, meaning that devices implementing any of these profiles can be operated on the same bus. The transmission medium is twisted pair using carrier signalling and it is known as the Euridis Bus. This first edition cancels and replaces the first edition of IEC 62056-31, issued in 1999, and constitutes a technical revision. The main technical changes are: - addition of a profile which makes use of the IEC 62056 DLMS/COSEM Application layer and COSEM object model, - review of the data link layer which is split into two parts: a pure Data Link layer; a "Support Manager" entity managing the communication media; - ability to negotiate the communication speed, bringing baud rate up to 9 600 bauds.