Modbus - Wikipedia
https://en.wikipedia.org/wiki/Modbus
Modbus is a data communications protocol originally published by Modicon (now Schneider Electric) in 1979 for use with its programmable logic controllers (PLCs).
The Modbus Organization
https://modbus.org/
Modbus Organization Replaces Master-Slave with Client-Server The Modbus Organization Board of Trustees announces it is expunging all occurrences of inappropriate language of the query and...
What is Modbus? | Types of Modbus | RealPars
https://realpars.com/modbus/
Modbus as an "Open Protocol". Depending on the process automation equipment manufacturer, a very specific or proprietary language is used or it may be a language that is commonly open to the industry.
Modbus Tutorial from Control Solutions
https://www.csimn.com/CSI_pages/Modbus101.html
Modbus is an industrial protocol standard that was created by Modicon, now Schneider Electric, in the late 1970's for Modbus remains the most widely available protocol for connecting industrial devices.