NEMA BS 31015-2023

ClimateTalk is a universal language for innovative, cost-effective solutions that optimize performance, efficiency and home comfort. The ClimateTalk Open Standards define a set of messages and commands to enable interoperability, enhanced user interface, and machine to machine control independent of the physical layer connecting the devices.

The messages and commands defined by ClimateTalk Information Model are the presentation and application layers as defined by the OSI Model . ClimateTalk Applications are fully defined at Layer 7 of the OSI model by a combination of a Device Specific Application Profile, an Application Specification, and the Command Reference.

Below the application layer, ClimateTalk messages can be carried over any physical medium following the OSI model. CT-485 and CT-LWP are wired serial physical and network layers designed to support the formation of ClimateTalk networks and transport ClimateTalk messages, but other OSI based protocols –including wireless transports – can be used as well.

CT-485 is a Physical, Data Link, and Networking set of specifications that define one of the physical media over which ClimateTalk messages are sent. CT-485 is a variant of EIA/TIA-485 standards with provisions against incorrect wiring and grounding requirements that meet the needs of residential systems.

This document defines the Serial Hardware requirements for CT-485, which corresponds to OSI Layer 1. The Physical Specification defines the electrical transmission requirements for implementing ClimateTalk over CT-485. All hardware is defined in this specification and all devices must meet the requirements in this document to be certified as CT-485 devices. See Figure 1 – OSI Layers for a CT-485 Implementation for a diagram of relevant standards.