"esent invention. [0020]FIG. 3A is block diagram displaying some of the components of the mobile terminal unit of FIG. 2. [0021]FIG. 3B is a block diagram displaying some of the components of the electronic identifier unit of FIG. 2. [0022]FIG. 4 is a schematic of a fixed-location facility, or trailer yard, including a yard processor, several trailers, and a yard tractor, based on an embodiment of" . . . .