Two way means bidirectional or in other words- something can pass in both directions. This circuit is a bidirectional RS232. It is possible to transmit and receive data through it.
The reason for using this device is to improve the function of the serial I/O of a computer. The circuit converts the serial port into an 8-bit parallel port (also bidirectional).
This way you've got a serial to parallel and parallel to serial converter that can simultaneously receive and transmit independent from each other.
It is also called Universal Asynchronous Receiver/Transmitter, or simply UART.
The RT clock frequency is 19.2 kHz which generates a data transmission speed of 1200 baud. Before the circuit can be used by a computer, it must be dimensioned first by
the following command:
30 means 300 baud
n means no parity bit
8 means 8 data bits
2 means 2 stop bits
Table A shows the positions of the DIP switch for every data format. The DSR and DTR pins of an IBM PC's sub D 25 pins connector must be connected together.
When no protocol is available, connect the lines RTS and CTR together.
Electronic Circuits volume 1.0 - Circuit Nr. 77
The complete data of the electronic circuit described above can be found in the following book and is available from Amazon.com.
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