Connection - Alphatech (en)

Basic module NUDV  is supplied in three variants – with two NUDV-02 buttons, one NUDV-01 button and without buttons, type NUDV-00.

To ensure the basic function the telephone line can be connected – the terminal marked as "a b  LINE". It is connected in the same way as any telephone to any branch exchange. The doorphone’s circuits are supplied from telephone line, so that nothing should be connected for voice communication.
If one or two switches are necessary to be used, the A.C. voltage of min. 10Vst - max. 15Vst or D.C. voltage of min. 12Vss to max. 18Vss must be energized to "12V" terminal. This source loading depends on number of modules, since it simultaneously serves feeding of lighting through visiting cards – at max. number of connected modules the demand will not exceed 300mA. This source can be also used for feeding of lock(s), and then it is necessary to consider the electrical lock demand. In practice the alternating feeder 12V/1A mostly meets these demands.
The connection of switch contact terminals is shown on picture. The "NO" designation means an idle-disconnected contact, "COM" means a pin contact (middle) and  "NC" means an idle-connected contact. The contacts of both switches are galvanically isolated each other and from other doorphone circuits. The variants of connection are shown:

The "G" Faston 2.8mm terminal protects against static electricity – to be connected to earthing.
The "VOLUME" trimmer serves to the adjustment of loudspeaker volume, it has no effect to other doorphone features. The "MIC" trimmer (placed under PDV board) provides the adjustment of microphone volume. Such adjustment can improve the feature of speech way, e.g. by ambient noise in the street.
The "EXPANSION" marked connector serves the connection of extending modules by means of flat cable.
The "PRG" marked connector provides the doorphone adjustment from PC by means of serial cable (KAB) and serves to the service for diagnostics and new software load.
The "HEAT" jumper serves the switching of board heating. This function requires the connection of 12V supply on "12V" marked terminal.
The "SERVICE" jumper serves to direct access to programming. It can be used, for example by absence of password for programming.    
Setting voice communication – position  trimmers are presetting from manufacture and in majority case agree with, therefore changes setting altering only in necessary case.
Trimmer "MIC" be instrumental to setting loudness of microphone, trimmer "SPK" be instrumental to setting loudness loudspeaker.  In this version is big reserve in gain, therefore isn't recommended adjust more than on half, typical is in from minimum gain. Trimmer "TRH" be instrumental to setting levels activation of microphone, it means, so as doorphone "non whoop" owing to  acoustic loop so selection, which direction has priority, whether from microphone, or into loudspeaker. Level from which volume with "switch on" direction from microphone doorphone setting trimmer „TRH". This setting interact level surrounding  noise and setting gain of microphone „MIC".
Progress of setting: trimmer MIC and SPK setting in 1/4 from minimum loudness (minimum is sense turning left), trimmer TRH setting in central position.  At conversation connection stilly talk and trimmer TRH turning from central value  direction to the left so, till you will on the side phone (in building) hear. Gain of loudspeaker, in some case of microphone set-up according to needs.