User's Manual

SIM840W EVB User Guide
SIM840W-EVB_UGD_V1.00 13 2011-06-22
3.5 RS232 Interface
Figure 8: Serial Ports
Serial Port 1——MAIN Interface
Serial Port 2——DEGUG Interface
Main Interface:
Pin Signal I/O Description
1 DCD O Data carrier detection
2 TXD O Transmit data
3 RXD I Receive data
4 DTR I Data Terminal Ready
5 GND GND
7 RTS I Request to Send
8 CTS O Clear to Send
9 RI O Ring Indicator
Debug Interface:
Pin Signal I/O Description
2 DEBUG_TX O Transmit data
3 DEBUG_RX I Receive data
5 GND GND