External speaker - Alphatech (en)

Additional speaker is another module in the kit NUDV doorphone. Using find in a noisy environment where the basic volume does not meet. This module includes an amplifier powered by a flat cable from the basic module. Therefore, the basic condition to have an external power module. Source signal is obtained by connecting two wires parallel to the speaker in the base module (plug) - is located under the removable CPU board. Polarity of this connection may be possible to eliminate acoustic feedback. Set the desired volume can be a screwdriver in the indicated slot.