Thanks AlexUT,
I understand this pretty well, in theory great, but in our environment just not realistic at all!
Mainly these machines e.g. harvesters work during night time or around the clock and "parked" in the field no shed/ garage around. Training people to use a laptop with Wifi etc (I have a 3G Lan router incl. Wifi) for retrieving data for example in a car - NO WAY!
My existing unit has a SD card slot, just very simple.
As said our plan is to use both possibilty, if possible data transfer (and other functions, like trouble shooting) via 3G Lan router and SD card as backup and in situation where there is no coverage or bad signal.
A pity, Unitronic's Visilogic is an excellent software - the best I have seen so far!