IEC 62056-3-1:20 21作为IEC 62056-3-1:20 21 RLV提供，其中包含国际标准及其红线版本，显示了与上一版本相比技术内容的所有变化。 IEC 62056-3-1:20 21描述了两组简档:第一组简档允许客户端和服务器之间的双向通信。这组配置文件由三个配置文件组成，允许与通电或不通电的站进行本地总线数据交换。对于非通电站，总线为数据交换提供能量。支持三种不同的配置文件: ？基本配置文件:这个三层配置文件提供远程通信服务； 注1该第一个配置文件发表于IEC 61142:1993，并被称为Euridis标准。 ？DLMS配置文件:该配置文件允许使用IEC 61334 4 41中规定的DLMS服务；注2该第二个配置文件发布于IEC 62056-31:1999。 ？DLMS/COSEM配置文件:该配置文件允许使用分别在IEC 62056 5 3和IEC 62056 6 2中指定的DLMS/COSEM应用层和COSEM对象模型。 这三个配置文件使用相同的物理层，并且它们完全兼容，这意味着实现这些配置文件中的任何一个的设备都可以在同一条总线上运行。传输介质是使用载波信令的双绞线，并且它被称为Euridis总线。 第二组简档允许给定能量计量设备和客户能量管理系统之间的单向通信。第二组由三个轮廓组成。 子条款4.2.1至条款8规定了使用双绞线信令和条款9至9的双向通信。图5示出了使用双绞线信令的单向通信。 第二版取消并取代了2013年发布的第一版IEC 62056-3-1，构成技术修订。 与上一版相比，主要技术变化如下: ？添加利用IEC 62056 DLMS/COSEM应用层和COSEM对象模型的配置文件； ？回顾分为两部分的数据链路层: -纯数据链路层； -管理通信介质的“支持管理器”实体； ？能够协商通信速度，使波特率高达9 600波特。

IEC 62056-3-1:2021 is available as IEC 62056-3-1:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 62056-3-1:2021 describes two sets of profiles: the first set of profiles allows a bidirectional communication between a client and a server. This set of profiles is made of three profiles allowing 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: this three-layer profile provides remote communication services;
NOTE 1 This first profile was published in IEC 61142:1993 and became known as the Euridis standard.
？ profile with DLMS: this profile allows using DLMS services as specified in IEC 61334 4 41;
NOTE 2 This second profile was published in IEC 62056-31:1999.
？ profile with DLMS/COSEM: this profile allows using the DLMS/COSEM Application layer and the COSEM object model as specified in IEC 62056 5 3 and in IEC 62056 6 2 respectively.
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.
The second set of profiles allows unidirectional communication between a given Energy Metering device and a Customer Energy Management System. This second set is made up of three profiles.
Subclause 4.2.1 to Clause 8 included specify the bidirectional communication using twisted pair signalling and Clause 9 to 9.5 the unidirectional communication using twisted pair signalling.
This second edition cancels and replaces the first edition of IEC 62056-3-1, issued in 2013, and constitutes a technical revision.
The main technical changes with regard to the previous edition are as follows:
？ 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.