4.5 Lift Blocking Function

Blocking Procedure

The contact closes/opens whenever an alarm call cannot be set up. Connect the contact to the appropriate controller input of the lift/group of lifts. The control electronics shall ensure that, upon contact opening, the lifts that are in operation arrive in the nearest station and open the door.

Every CU and every splitter are equipped with the lift blocking contact. Refer to Subs. 2.1, PSTN/GSM/UMTS/VoIP Central Unit – Lift Blocking Contact Connector.

The lift blocking function will be enabled if:

  • no number is defined in the ALARM memory – the lift gets blocked immediately.
  • a number to a non-existent machine room (intercom) is defined – the lift gets blocked in 2 minutes.
  • a PSTN number is defined but no module is inserted – the lift gets blocked immediately.
  • the external line (PSTN, VoIP) is not functional – the lift gets blocked in 5 minutes. 
  • the dialtone is not detected –  the lift gets blocked in ca. 10 minutes (after the PSTN line test which does not detect the dialtone).
  • no SIM (GSM/UMTS) is inserted – the lift gets blocked in 5 minutes.
  • there is no signal (GSM/UMTS) – the lift gets blocked in 5 minutes (a very low signal does not cause blocking).
  • the capacity of the device feeding battery so low that the internal buses (audio units) get disconnected – the lift gets blocked when the internal bus gets disconnected.
  • 2N® Lift8 is off – the lift gets blocked immediately.


  • The PSTN line test is carried out every hour. If an error is detected, the line test is repeated every 2 minutes until the line is evaluated OK again.
  • If parameter 902 is set to 0, the line test is not performed and the line is not blocked when the dial tone is not detected.

The lift blocking function will be disabled if:

  • the line works for 1 minute at least (PSTN, VoIP).
  • a power supply is connected to recharge the battery.


  • This function may be mandatory if the applicable regulations valid for the country and time of installation require so.