I hate the Tachograph. There's too much going on, and it's always busted. If one part of it is screwed up, it messes up all the rest of it. The power drain on it causes the batteries on MVs you buy to be completely ruined 99% of the time. We are always having trouble with our tachographs while the simpler trucks with a simple little dial for speed and another one for RPMs always seem to be working.