General master key system

General master key system (GMK-system)

The presence of several locking groups of cylinders in a common locking system is called a general master key system. In addition, central functions can also be integrated into this type of system.

If a key is present across all cylinders, it is referred to as a GHS key. Keys that close all cylinders in the group are called group keys.


General - master key - system

The following closures can be seen in the picture:

  • key S.2 closes the cylinders pos. 1 to pos. 3
  • key S.3 closes cylinders pos. 3 to pos. 5, etc.
  • the keys thereby lock the mentioned cylinder groups
  • key S.1 locks all cylinders - Since there are several locking groups in the system, this key is then called the general master key.
  • the number of the respective keys does not play a role