RS-232 interface does not work properly. 'Set' commands are processed as expected but 'Read' commands cause the device to change state. Contacted Xantech and they acknowledge the bug but claim the device works because you can send commands. I was first told there would be a firmware fix within a month but once the month had elapsed I was told there would not be a fix until next year 2013 which was 6 months later. In the meantime, I stuck with a half-functional product that doesn't do what I need it to despite being advertised as an RS-232 capable device. I purchased this device over other DIGI-5 devices specifically because of the RS-232 interface.