DEVICE FOR CONTACTLESS TRANSMISSION OF DTMF SIGNALS

摘要

In the device there is used a standard portable keyboard (1) of voice frequency dialling with built-in dynamic speaker (2) whilst in the receiving circuit of the voice frequency dialling there is a decoder of the voice frequency dialling signal (7), at the enter there is a condenser (5) and resistance (6), and one end of the receiving circuit is connected with the common ground (4). Directly on the enter of the receiving circuit of the voice frequency dialling there is the beginning of the induction coil (3) connected, whilst the end of the induction coil (3) is connected with the common ground (4) of the receiving circuit of the voice frequency dialling.