In existing buildings, bell system modules can often be found in sub-distributions as built-in devices. With the dSready "IC Klingel Modul", two bell buttons with an 8 or 12 volt AC signal can be connected. The signals are galvanically separated and transferred to the digitalSTROM system. Both inputs are assigned their own dSID. This is how the first and second floor of a two-family house can be defined. The digitalSTROM statuses of the system are indicated by an LED on the front.