Circuit design for the mini-type data communication equipment

Many kinds of communication and data-transmitting systems have used data communications equipment (DCE) to exchange information. The special-purpose DCE has a very important practical value. This work proposed the circuit design for a new kind of mini-type distance data exchange device. It consists of a small number of integrated circuits, telephone dial device, modulation device, central processing unit, button input device and display device. The system and circuit design is described in detail. It can be used to transmit data through a public switched telephone network. It is suitable for constructing a mini scale communication network at low cost for data transmission through the PSTN.