Serial Interfaces - Quectel M35 User Manual

For the choice of a rechargeable or non-chargeable coin-cell battery, please visit http://www.sii.co.jp/en/.
NOTE
If the module is only powered by VRTC , the real time will have an error about 5 minutes a day. If you want
to keep an accurate real time, please use VBAT to supply the RTC core.
3.7.

Serial Interfaces

The module provides two serial ports: UART Port and Debug Port. 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: Request to send.

CTS: Clear to send.

DTR: DTE is ready and inform DCE (this pin can wake up the module).

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
Hardware flow control is disabled 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 the
document [1].
The Debug Port:

DBG_TXD: Send data to the COM port of computer.

DBG_RXD: Receive data from the COM port of computer.
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