Electropneumatic parking brake modulator

An electropneumatic parking brake modulator for controlling a parking brake function of brakes of at least one trailer vehicle in a tractor-trailer combination, the modulator comprising:

• a first valve device for aerating and deaerating at least one of spring brake cylinders and spring store parts of combined spring store/diaphragm trailer brake cylinders;
• a first select-high valve, by which the higher of the prevailing pressure downstream of the first valve device and a service brake pressure is provided for aerating the at least one of the spring brake cylinders and the spring store parts of the combined spring store/diaphragm trailer brake cylinders;
• at least one compressed air reservoir inlet for aerating at least one compressed air line with compressed air from a compressed air reservoir of the tractor;
• at least one compressed air reservoir outlet;
• at least one compressed air control outlet;
• a compressed air line to the at least one compressed air control outlet;
• a second valve device for aerating and deaerating the at least one compressed air reservoir outlet;
• and
• an integrated tractor vehicle protection valve that automatically shuts off the compressed air line to the at least one compressed air control outlet when reservoir pressure provided for the at least one trailer vehicle falls below a predetermined threshold value.