Telephone set with a bidirectional infrared link between handset and fixed module connected to a subscriber's line.

摘要

1. Telephone set having a bidirectional infrared link (4) between handset (3) and fixed module (1) connected to a subscriber telephone line (2), the fixed module (1) comprising an analog-digital converter (150) and a digital-analog converter (151) both coupled to the telephone line (2) and means respectively between said converters and said infrared link for emitting (170, 172) and receiving (174, 171) digital signals, and the handset (3) comprising means for emitting (370, 372) and receiving (374, 371) digital signals through said infrared link (4), a microphone (M), an analog-digital converter (350) between the microphone and the handset emitting means, an earphone (E), a digital-analog converter (351) between the handset receiving means and the earphone, digital dialing means (380, 30) connectable to the handset emitting means (370, 372), and off-hook and on-hook simulating means (382, 30) connectable to the handset emitting means (370, 372), characterized in that the handset (3) comprises means (30, 311) for validating a personal and confidential number assigned to the handset (3), the personal number being dialed by the user with the help of the dialing means (380) and transmitted after validation through the infrared link (370, 372, 4, 174, 171) from the handset to the fixed module (1) after energization of the on-hook simulating means (382, 30) and before seizing of the telephone line (2), and charge counting means (30, 32) for incrementing a stored call-charge account responsive to charge digital words and for displaying the stored call-charge account on displaying units (390) in the handset, and in that the fixed module (1) comprises means (10, 12) for storing the personal number transmitted by the handset (3), means (14) for detecting charge pulses carried on the telephone line (2), means (10, 12) for counting the detected charge pulses, means (10, 154) for transmitting a charge digital word through the infrared link (170, 172, 4, 374, 371) to the handset charge counting means (30, 32, 390) in response to each detected charge pulse, and means (10, 16) coupled to the telephone line (2) for transmitting the personal number and the charge account stored in the fixed module (1) onto the telephone line after the on-hook simulating means (382, 30) breaks off the telephone call and when the management means is in a receiving condition.