SENA HD1300 - Manual (Page 9)

Starter Kit and User Manual for the HelloDevice 1300
9
3.4 Serial Communication Interface
§ RS232/485 communication mode switching by sliding switch
§ DB9 connector for RS232/RS485 communication
§ 150 ~ 38400 baud rate
Pin assignment of 9-pin DSUB connector is shown in Figure 3.4. All the signal lines for RS232 and RS485
communication are included in the HelloDevice serial port. Communication mode is switched by using
RS232/485 conversion switch, which is represented as SW2 in the main board.
Pin No. Symbol Description Function
1 RS485+ RX485+ 485 data line
2 RxD Receive Data Data Input
3 TxD Send Data Data Output
4 RS485- RX485- 485 data line
5 GND Signal Ground -
6 NC Not connected -
7 RTS Ready To Send Handshake Output
(+12V=Ready to Rx, -12V=Not Ready to Rx)
8 CTS Clear To Send Data sent
9 NC Not connected Data sent only at +3V ~ 12V
Figure 3.4. Pin Assignment of the HelloDevice DSUB Connector
6=DSR 9=NC
7=RTS 8=CTS
1=RS485+
2=RxD
5=GND
4=RS485-
3=TxD