Rs232C Monitor - Maker Factory ELECTRONICS EXPERIMENTS BOX Manual

2.71 RS232C monitor

Circuit 148: Simple RS232C monitor
Setup information
Install the two diodes and the two resistors as shown in Fig. 2.148. The two wire jumpers are next. Check
the placement on the board again.
Experiment
It is still used in systems, where PCs are utilized to control machines such as: the serial interface RS-232C
of a computer from the days of infancy. If you would like to connect an CNC milling machine or one of the
unrivalled practical PSION pocket computers (s3mx or s5mx), this present circuit can help to overcome
connection issues. If connected to the pins RxD (receive direction) and TxD (send direction), the red LED will
signal a positive voltage level. This corresponds to a Logical Zero. Likewise, the green LED stands for a nega-
tive voltage level, thus, a Logical One.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.148.
Circuit 149: Pin assignment of the RS-232C interface
Setup information
The pin assignment of the RS-232C interface is shown for the 9-pin connector, which is often used.
174
Components required:
1 x red LED, 1 x green
LED, 1 x 1 kΩ resis-
tor, 1 x 2.2 kΩ resistor,
1 x breadboard
Fig. 2.148: Simple RS-232C
monitor
Components required:
none
Fig. 2.149: Pin assignment of the
RS-232C interface