Documentation
Free to download. From Version 2.0, released as SysML model. Archived releases are text plus XML schema. Developer tools for implementing the standard are hosted on GitHub.
Free to download from OPC Foundation. Representation of the MTConnect model in UA.
NC-Link by the CNC machine tool interconnection communication protocol standard alliance under CMTBA (China). The full spec and developer tools are at http://www.nc-link.org.cn/#/norm.
Free to download. Additional documentation for implementing B2MML with MTConnect is available on the MTConnect User Portal wiki at www.mtcup.org/en/B2MML.