The electronics manufacturers see two problems with adopting the ISOBUS standard as currently written. “One of the problems we face in North America is that not everyone is willing to play nice with each other,” says David King, marketing manager for Ag Leader. “While companies promote that they meet the ISOBUS standard, not everybody's ISO equipment can be read by everybody's VT.”

King says some OEMs that market themselves as ISO-complaint are still using language that only their brand of equipment can understand to control certain functions, namely steering and vehicle functions.

Deane Malott, director of marketing for AutoFarm, agrees: “The true concept of the ISO standard is that I should be able to take any task controller and plug it into any VT. The problem is, vendors are only halfway committed to that vision by keeping some functions proprietary.”

OEMs counter by saying that opening up their vehicle functions to third-party controllers is a liability risk they are not willing to take. “Machine control is core to our product and is not something we are going to give up,” says Kirk Wesley, Advanced Farming Systems global manager with Case IH. “Other companies can provide steering and implement functions, but we are not going to give them the code or ability to reach into our vehicles and change engine rpm, hydraulics or other settings that could put a tractor out of spec.”

A second reported problem is that the ISOBUS standard does not cover or support all of the functions that can be monitored and controlled by third-party controllers. This limits what aftermarket companies that make third-party controllers can offer under the ISOBUS standard.

“The VT can only recognize those functions that have been defined by the ISO standard, unless the VT has been programmed to display those functions,” Ag Leader's King says. “Some farmers are going to want more than what is provided in the ISOBUS protocol.”