SENA HD1300 - Manual (Page 32)

Starter Kit and User Manual for the HelloDevice 1300
32
Figure 6.2 RS232/485 communication mode switching
6.1.1 RS232 communication
Only 4 pins of RxD, TxD, RTS, and CTS are used in RS232 communication of the HelloDevice. You have to
make RS232 communication cable by using the connection shown in Figure 6.3.
Figure 6.3 RS232 communication cable connection diagram
RS232 mode RS485 mode
SW2 SW2
RxD
TxD
GND
RTS
CTS RxD
TxD
GND
RTS
CTS RxD
TxD
GND
RxD
TxD
GND
(a) Flow control = H/W (b) Flow control = None
HelloDevice HelloDevice User device User device
7=RTS 8=CTS
2=RxD
5=GND
3=TxD
HelloDevice serial port