摘要 |
<p>A method of detecting communications errors by coding messages as pictures is provided. Also provided is a communications method useable to safely communicate a message or a signal from a first safety approved entity (210) to a second safety approved entity (230) via a third, non-safety approved entity (220), comprising that each command is sent with the aid of a command message from the first to the second entity, an acknowledge message from the second to the first entity, and a go-ahead message from the first to the second entity.</p> |