A master key system is a locking system whereby selected keys can open a number of pre-defined doors. Master keying makes moving around in buildings easier, for example one key can unlock all the locks in your home (staircase, apartment, basement and mailbox door). However, each key can only open these doors that are assigned to it in the key locking system. Lock systems are suitable for private houses as well as apartment buildings, office buildings and other places with many doors.
KEYED TO DIFFER
Locks or cylinders, each of which is combined differently from the others. Each different key operates only one lock or cylinder. They may be a part of a master key system if the system is designed so. But they can not be added into a master keys system later on without rekeying.
When they are not designed to be part of a master key system, the codes are so called random codes and they are not allowed to be master keyed.
KEYED ALIKE
Two or more locks or cylinders which have the same key combination. Number of locks can be operated by the same key. They may be a part of a master key system if the system is designed so. But they can not be added into a master keys system later on without rekeying.
When they are not designed to be part of a master key system, the codes are so called random codes and they are not allowed to be master keyed.
CENTRAL LOCKING
Central key system, also called maison or common key system. A keying system in which one or more cylinders are opened by every key or by large number of different keys in the system. For example a lock or cylinder of a gate or main entrance door.
The openings for central locks should be created group by group. No individual key of its own for the central lock.
MASTER KEYING
The simplest master key system has two levels of keying and is considered the basic level of master keying. The less powerful keys at the bottom are called individual keys. Each individual key operates only one lock, or one group of keyed alike locks. The more powerful key at the top is called the master key.
GRAND MASTER KEYING
3-level system is two or more 2-level systems tied together under a higher level key called a grand master key.
