Phone signal [Type DUO]
The DUO signals incoming calls both audibly and optically: it lights up with roughly five watts per second and emits a two-tone signal at 105 db (A)/1 m. The flash frequency and the signal tone can be set individually. Breaks in the ringing current are bridgeable. The DUO is intended for wall mounting and is controlled by the integrated telephone connecting relay. Other connecting types are possible, such as via a doorbell.
