Automatic setting system for modem signal transmission level

Abstract

Abstract PURPOSE:To automatically set a modem signal transmission level and to easily set a facsimile, a data terminal equipment, etc., by setting the modem transmis sion level based on the magnitude of the current detected by a current detection means. CONSTITUTION:A coil 10 separates line and powder source systems. The telephone line becomes a constant value capable of the loop closing of dc resistance. A coil 11 serially provided on the line generates magnetic field proportional to the magnitude of the current of telephone lines L1 and L2, and a hole element 1 generates voltage proportional to the current. The voltage produced by the hole element 1 is amplified by an amplifier 2 and conveyed through an A/D converter 3 to a control part 4. On the other hand, the control part 4 calculates the lines loss of the telephone line based on the voltage value obtained from the A/D converter 3 and controls an attenator 6 so as to make a modem signal transmission level P the prescribed value. Therefore, the modem signal transmission level can be set according to the magnitude of the current of the telephone line.

Inventors

• 👤 Tadashi Hirota
• 👤 広田　正
• 👤 Satoru Saito
• 👤 悟 斉藤

Bibliographic Details