TELEPHONE AND DEMODULATOR

摘要

A computerized telephone that is capable of making enquiries directly to a data bank over the telephone line, of displaying the information retrieved and, when such information is a telephone number, of automatically dialling it. The telephone comprises an alpha-numerical keyboard (3), a display (6), a program data process (19), a ROM (2) and a RAM (21) associated with each other and said unit, an automatic dialling circuit (26), a modulator for modulating data for transmission by the telephone line and a demodulator (27) for demodulating signals from the line to produce data intelligible to the unit (19) which is programmed to command operations by means of the telephone line in dependence upon data received therefrom or derived from the keyboard (3). A demodulator is also described as comprising a signal shaper (27) basically in the form of a transistor (44) whose base is connected to the telephone line and whose collector produces a square wave output signal of the same frequency and phase as the fundamental harmonic of any alternating signal on said telephone line. The square wave signal is applied directly to the unit (19) for processing.