A method and apparatus for data interchange between a tractor vehicle and
a trailer vehicle coupled thereto. A first electronic device provided in
or on the tractor is connected via a data link to a second electronic
device provided in or on the trailer; the first and second devices being
connected to sensors and/or actuators for controlling operating functions
of the vehicle allocated thereto and for measuring status information.
Initiated by an information request, the first device sends request data
via the data link to the second device. The first device receives status
information via the data link sent by the second device in response to
the request data. The first device outputs, in a manner that correlates
with the trailer, the received status information by means of an output
device disposed on or in the tractor. The same output scheme is used for
both the tractor and trailer.