User's Manual

SIM900B EVB User Guide
SIM900B-EVB_UGD_V1.01 14 14.04.2010
4.1 Serial Interface
J1---RS232 Interface
Figure 11： J1 Interface
RS232 Interface Pin List:
Pin Signal I/O Description
1 TXD O Transmit data
2 RXD I Receive data
3 DCD O Data carrier detection
4 RI O Ring Indicator
5 CTS O Clear to Send
6 GND GND
7 DTR I Data Terminal Ready
8
DBG_RXD
I Receive data
9 RTS I Request to Send
10
DBG_TXD
O Transmit data