An electronic cassette is a microprocessor device, which control work of the whole doorphone system. Older models operating main and subordinate entrances had special types of electronic cassettes. CD-3100 doorphone uses one kind of electronic cassette, in which the installer defines what type of entrance it will support. Electronic cassette is supplied from the two-winding AC adapter.
It is possible to connect a battery to electronic cassette, which provides correct work of electronic cassette in case of loss of power in the grid. The electronic cassette has line balance potentiometer and INIT and RESET buttons used to restore the default settings of the cassette. EC-3100 electronic cassette is not compatible with EC-3000 and it cannot be used as its substitute.