IEC 62026-3:20 14规定了单个或多个控制器与控制电路设备或开关元件之间的接口系统。接口系统在一根电缆内使用两个导体对，其中一对提供差分通信介质，另一对为设备提供电源。本部分建立了组件与此类接口的互操作性的要求。IEC 62026-3的第三版取消并取代了2008年发布的第二版。这第三版构成技术修订。与上一版相比，主要变化如下: -第4组消息的规范(5.1.2)； -关于消息传递协议的澄清（5.2）； -添加I/O多播轮询消息(5.5.2和5.5.8)； -对奴隶行为的澄清（5.5.4和5.5.9)； -5.7中关于物理层（收发器）的澄清； -对电缆(8.2)的杂项更正/澄清； -关于EMC测试（9.2.10）和逻辑测试（9.3）的说明。

IEC 62026-3:2014 specifies an interface system between single or multiple controllers, and control circuit devices or switching elements. The interface system uses two conductor pairs within one cable - one of these pairs provides a differential communication medium and the other pair provides power to the devices. This part establishes requirements for the interoperability of components with such interfaces. This third edition of IEC 62026-3 cancels and replaces the second edition published in 2008. This third edition constitutes a technical revision. The main changes with respect to the previous edition are the followings:
- specification of group 4 messages (5.1.2);
- clarifications on messaging protocol (5.2);
- addition of I/O multicast poll messages (5.5.2 and 5.5.8);
- clarifications on slave behaviour (5.5.4 and 5.5.9);
- clarifications on physical layer (transceiver) in 5.7;
- miscellaneous corrections/clarifications on cable (8.2);
- clarifications on EMC testing (9.2.10) and logical testing (9.3).