5
RS232 Interface
5.1
Pin-out
5.2
Signals
Pin
DTE
Signal
DTE to DCE
Direction
DCE to DTE
Direction
Description
1
CD
Input
Output
Not connected
2
RxD
Input
Output
Received data
3
TxD
Output
Input
Transmitted data
4
DTR
Output
Input
Not Connected
5
GND
N/A
N/A
Signal ground
6
DSR
Input
Output
Not Connected
7
RTS
Output
Input
Request to Send
8
CTS
Input
Output
Clear to Send
9
Vcc
Input
Input
Power supply
5.3.
Factory Settings
The factory settings of COM port are as follows:
Baud rate: 19200 bps
Data bit: 8
Parity: none
Stop bit: 1
Flow control: H/W
Others: please refer to section 7.5 AT Command Set.
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