Analogue Board
The analogue board provides the interface circuitry between the monitored and control telephone lines and the microprocessor. The board contains the following devices ;
U1 = OP490 Quad Op-Amp U2 = Mitel MT8870CE DTMF Decoder U3 = Motorola MC145442 V.21 300Baud Modem U4 = LM358N U5 = Phillips 74HC157PThe board also contain a 25-way female D-type connector that provides the electrical interface to the monitored/control lines. Alternatively, it provides an RS-232 interface thereby enabling the direct connection of a PC running the Dialog software.
Read more about this topic: Monolog
Famous quotes containing the words analogue and/or board:
“Human language appears to be a unique phenomenon, without significant analogue in the animal world.”
—Noam Chomsky (b. 1928)
“And they heaved a mighty breath, every soul on board but me,
As they saw her nose again pointing handsome out to sea;
But all that I could think of, in the darkness and the cold,
Was just that I was leaving home and my folks were growing old.”
—Robert Louis Stevenson (1850–1894)