| 摘要 |
The telephone set includes a changeover switch (GU) with poles (S1, Si) to switch an acoustic transducer (Lsp) on and off. A calling device such as an electronic alarm (W) and a speech switch are also present. A potentiometer (P1) controls the amplitude of the alarm and a second potentiometer (P2) regulates the loudness of the speech and audible tones. Connections (a, b) are provided for the subscriber line. An incoming call is transferred to the alarm (W) by way of a short-circuited coupling resistor (R1) and by way of the first potentiometer to a sound transducer. Lifting up the handset disconnects the alarm and prevents the dialling process from being heard. |
