1. RS-232 Port

The RS-232 port of this board is a D-SUB 9-pin male connector. The pin map is as follows.


Number Name Description Level I/O Wiring
1 DCD Data Carrier Detect RS-232 In Optional
2 RXD Receive Data RS-232 In Required
3 TXD Transmit Data RS-232 Out Required
4 DTR Data Terminal Ready RS-232 Out Optional
5 GND Ground Ground - Required
6 DSR Data Set Ready RS-232 In Optional
7 RTS Request To Send RS-232 Out Optional
8 CTS Clear To Send RS-232 In Optional
9 RI Ring Indicator RS-232 In Optional

2. SLAVE ID Switch

A slave ID is used when PHPoC shield identifies each smart expansion board. So, each smart expansion board, which is connected to a PHPoC shield, should have a unique slave ID. The slave ID can be set one of the numbers from 1 to 14 by 4 DIP switches as follows:


3. LED

This board has 9 LEDs.

Name Quantity Type Color Operation
STS 1 SMD red ID setting is normal > repeats on / off every 1 second
ID setting is incorrect > blinks fast
TX 2 DIP, SMD green blinks when sending data to the serial port
RX 2 DIP, SMD yellow blinks when receiving data to the serial port
CTS 1 SMD yellow ON when CTS signal is ON
RTS 1 SMD green ON when RTS signal is ON
DSR 1 SMD yellow ON when DSR signal is ON
DTR 1 SMD green ON when DTR signal is ON