LE910Cx HW User Guide
1VV0301298 Rev. 33
Page 70 of 128
2021-06-29
Not Subject to NDA
RS232 Pin#
Signal
Pad No.
Name
Usage
4
DTR - DTR_UART
M14
Data Terminal
Ready
Input to LE910Cx
that controls the
DTE READY
condition
5
GND
A2, B13, D4…
Ground
Ground
6
DSR - DSR_UART
P14
Data Set Ready
Output from
LE910Cx that
indicates that the
module is ready
7
RTS - RTS_UART
L14
Request to Send
Input to LE910Cx
controlling the
Hardware flow
control
8
CTS - CTS_UART
P15
Clear to Send
Output from
LE910Cx controlling
the Hardware flow
control
9
RI - RI_UART
R14
Ring Indicator
Output from
LE910Cx indicating
the Incoming call
condition
Table 28: Modem Serial Port 1 Signals
Note:
DCD, DTR, DSR, RI signals that are not used for UART
functions can be configured as GPIO using AT commands.
Note:
To avoid a back-powering effect, it is recommended to prevent
any HIGH logic level signal from being applied to the module’s digital
pins when it is powered OFF or during an ON/OFF transition.
Note:
For minimum implementations, only the TXD and RXD lines
need be connected. The other lines can be left open provided a
software flow control is implemented.