Letter framework
A letter tray or mail sorting locker is a specialized system for the manual distribution of letters etc. to the individual postal rates .
Letter boxes were to be found at the post office wherever mail was sorted. So they were also part of the usual equipment of rail mail cars and ÜpU buses ( overland mail with rework ). Some trusses were labeled according to a fixed scheme, but often the labeling of the trusses was also the responsibility of the respective post office officials. Since the more trusses are available, the more detailed the sorting, the sorting devices have been optimized to contain as many compartments as possible. In confined spaces, e.g. B. in rail mail cars, some trusses were u as folding doors. Ä. Designed. Since mail is now only processed in stationary, automated letter centers , distribution frames can only be found there for manual sorting of non-machine-compatible mail and in the preparation centers and delivery bases for sorting incoming mail according to delivery districts and aisle sequence.