Powerbot Virtual Guard Boundary System detail

Measurements were made of optical signals used in the Virtual Guard version of "virtual walls" used by Samsung, the same on Powerbot and Navibot.
This system uses a signal from the robot to activate the Guard only when nearby to save the battery in the Guard. Technical details found posted at
http://www.robotreviews.com/chat/viewtopic.php?f=4&t=20151&p=145468#p145468
Newer models in the U.S. since 2016 have switched to mag strip boundaries similar to Neato Robotics. The optical Virtual Guards lack focus of the beams and can be confused by reflections off walls, so is not a perfect system. Broad beams can work with random navigation robots like the Roomba on which originally used, but the systematic guided robots need to probe and map the shape of boundaries.

Activation Signal Change

An unusual firmware update over WiFi happened though not shown on the smartphone, which appears to have changed the Virtual Guard activation signal from the Powerbot. The Virtual Guard supplied with the original 9250 model imported from Australia no longer works, apparently not responding to the new signal.
For signal details see http://www.robotreviews.com/chat/viewtopic.php?p=145637#p145637
The update occurred in the U.S. where new models have mag strip boundary marking instead of Virtual Guards. Yet some Virtual Guard models have been sold in Europe.