Activate login mode:
To activate the login mode on the Troll, open the menu with the Menu key (M) and select 
System settings with the Settings key. 
Open the 9-9-1 menu.
The number of registered DuoFern devices is displayed. In our example, one device is logged in.
Switch the respective DuoFern device to the login mode.
Start the login process with the setting key.
On flashes in the display.
After successful registration, the new number of registered devices is displayed.
Log on the next DuoFern device or return to the menu selection using the menu button (M).
Note! Setting DuoFern mode - DuoFern receiver
If the Troll is registered with a DuoFern control panel such as HomePilot® type 9496-3, DuoFern hand control panel type 9493-1, HomeTimer type 9498 or with another Troll Comfort DuoFern type 5665, the DuoFern mode should be changed to receiver on the Troll. The Troll Comfort DuoFern also has a complete time program; by switching to receiver, the Troll Comfort DuoFern's own switching time program is deactivated. Menu item 9-9-2 to 1 (receiver)