2N Helios User And Service Manual page 24

Power
supply
AC or DC
12V
Tel.
line
Never switch 230 or 120 V mains voltage directly!!!
If you do not have an electric lock and want to have one, you should select a 12
V lock, this being the most common type. Connect the lock according to the figure,
which shows the button backlight supply too (see later).
Dc-supplied lock: Practically all locks can be dc and ac supplied. The ac supply is
more advantageous because the lock buzzes, which is the clearest signalling method
however to use a dc supply lock (from batteries, e.g.), you are recommended to equip
Helios with acoustic signalling (continuous tone during the whole switch activation
time).
Caution: If the lock power supply fails and the telephone system carries on working, the
keypad-equipped Helios system is unaware of the failure the switch will be password-
activated and the activation is acoustically signalled, but the electric lock will not work
because of the lack of power.
Typical Button Backlight Power Supply
Helios features a high-quality white-LED name plate backlight. This backlight shows
low power requirements, long life and even illumination of all name plates. If a standard
12 V electric lock (see above) is connected to Helios, the backlight can be powered
using the lock power supply. Connect the power supply as shown in the figure. Just
make sure that the power supply (adapter transformer) is able to supply the required
El. lock
24