Wireless Doorbells have a Doorbell Button transmitter which
generates a radio signal when the Button is pressed.
This signal is detected by the internal Doorbell Receiver and generates a ring. In and around the building there is no limit to the number of Wireless Doorbell devices that can be placed, as each only detects the signal.
Most Wireless Doorbell devices can detect at least 2 individual Bell button transmitters and if the device has at least 2 ringtone selections, depending on the pressed Button, different sounds can be generated, i.e. "front door/back door" operation.
Grothe Wireless Doorbells allow the connection of an unlimited number of Receiving devices to one Bell button transmitter.
One. however, 15-20 Bell button transmitters can be connected to the Receiving device.
It is possible according to the request combine the connection of different Bell button transmitters and Receivers between (matrix connection).
UPVC- and metal door frames: wireless radio signals cannot pass through metal and therefore Bell buttons transmitters should be avoided for installing buttons to UPVC door frames.
In places where UPVC door frames are installed, it is better to fasten the Bell button transmitter to the exterior wall or door, if it is a composite type.
If a short wire can be inserted into the building through the UPVC door frame, it can
the solution is to be a "wired-to-wireless" extension. ( Bell button- transmitter
In this case, is installed in the hall of the building and the first signal from the visitor reaches the Transmitter through a normal Bell button and a piece of wire
from the front door).
Radio signal strength: standard distances 50 m, 100 m, 150 m, and 200 m referring to the distance up to which the Doorbell receiver detects the Bell push-
transmitter signal in "open field conditions", i.e. without signal-damping walls.
"Open field conditions" is the standard that all manufacturers use instead of saying "typical"
Wireless can be considered minimally suitable for use Doorbells from a distance of 100 m if the Bell button transmitter is located on the outer wall or only slightly away from the building (at the gate).
With a distance of 200 m, Doorbells would be more suitable for large buildings with thick walls or taking mobile Doorbell receivers to gardens/ office premises/company warehouses/ just to outdoor areas.
Then the walls of the building should not be insulated with foil-backed insulation or
there should be no foil-covered insulation in the walls of the building.
We offer Grothe MISTRAL and CALIMA models for an extra large standard radio- range 
for distances of 250 m and 500 m, which can be further extended by connecting
additional signal intermediate amplifier for  Receiver.
Wireless Bell button transmitters have internal batteries connection option, 2 x 1.5 V type AAA on Grothe devices.
An external power source (Grothe Bell- transformer) with a voltage of 6-12 VDC is an option. The receiving devices can be used for power different batteries, a built-in and rechargeable battery, or an external power source (Grothe Bell- transformer) with a voltage of 6-12 VDC.