According to TEK17 (Technical Regulations to the Planning and Building Act), specifically § 11-13, it is the owner's responsibility to ensure that smoke detectors are functional and tested regularly.
Functional testing of all smoke detectors should be carried out at least once a month to meet the requirements of NS-EN 14604, which is the standard for smoke detectors in Europe, including Norway.
See instructions for functional testing in the article Installation of Abra Fire Protection in private homes under the heading Functional Test. You can also find relevant information in the article Functional test of fire protection and alarm station connection.
In addition to testing each individual smoke detector, the owner of the property is responsible for verifying that the series connection between smoke detectors works. When conducting a functional test of one smoke detector, all other smoke detectors in the dwelling unit (connected to the same Linkbox+) should also sound an alarm signal.
If you have activated the connection to the alarm station, carrying out a functional test will automatically check that the connection to the alarm station is working as it should.