| 摘要 |
The caller can select and signal to a specific i.e. an apartment or office from a group (A11,A12,A21,A22,A31,A32) in a building, each unit having a signal indicator (S11,S12,S21,S22, S31,S32). A decoder (DEC) in each has a digital calling address, and can activate the unit signal indicator on recognition of the corresp. digital calling address. A circuit (L), incorporating at least one signal conductor, is connected to each decoder, and a central unit (1) incorporating a display (3) and a selector (17) includes a central processor (CPU), a read only memory (ROM), and a reading/printing memory (RAM). - The selector (17) incorporates a stage increasing switch (S1+,S2+) and one for stage redn. (S1-,S2-) for transmission of corresp. signals to the central unit for each type of identification information. A signalling switch (S3) transmits a ringing signal to the central processor. The central unit display (3) presents a text corresp. to the digital data transmitted to the central processor (CPU). (Provisional basic advised week 89/25)(2/4) |
