acoustic telephone modern - data transfer via telephone lines

acoustic telephone modem elektor february 1983 The modem described here is a circuit that is designed to send and receive digital information via the normai telephone lines. It enables the interconnection of two computers (or a terminal and a computer) even though they are physically separated by a large distance. The circuit provides a minimum data transfer rate of 600 Baud. The modem is compatible with an RS 232 interface and is acoustically coupled with the telephone receiver handset. A safety circuit is also incorporated to prevent the modem from switching to transmit during data reception. acoustic telephone modem data transfer via telephone lines J.J.M. Habets and C.A. Truijens 2-42 The term "modem" is a contraction of the two words modulator and demodulator. At one end of the data transmission line (for us that usually means a telephone line) the digital information is transmitted in a modu lated form and then demodulated at the other end to restore the original data. The p...