SIM300D EVB User Guide
SIM300D-EVB_UGD_V1.01 Page 11 of 19
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
