Serial Interfaces - Quectel M12 Hardware Design

M12 Hardware Design
Figure 17: Seiko XH414H-IV01E Charge Characteristic

3.8. Serial interfaces

The module provides three unbalanced asynchronous serial ports including UART, Debug Port
and UART3.The module is designed as a DCE (Data Communication Equipment), following the
traditional DCE-DTE (Data Terminal Equipment) connection. Autobauding function supports
baud rate from 4800bps to 115200bps.
The UART Port:

TXD: Send data to RXD of DTE

RXD: Receive data from TXD of DTE

RTS: Requests to send

CTS: Clear to send

DTR: DTE is ready and inform DCE (this pin can wake the module up)

RI: Ring indicator (when the call, SMS, data of the module are coming, the module will
output signal to inform DTE)

DCD: Data carrier detection (The validity of this pin demonstrates the communication link is
set up)
Note: The module disables hardware flow control by default. When hardware flow control is
required, RTS and CTS should be connected to the host. AT command "AT+IFC=2,2" is used
to enable hardware flow control. AT command "AT+IFC=0,0" is used to disable the hardware
flow control. For more details, please refer to document [1].
The Debug Port:
M12_Hardware_Design_V3.3 - 37 -