GSM/GPRS Module Series
M66 Hardware Design
M66_Hardware_Design Confidential / Released 33 / 80
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.
The Auxiliary UART Port:
TXD_AUX: Send data to the RXD of DTE.
RXD_AUX: Receive data from the TXD of DTE.
The logic levels are described in the following table.
Table 7: Logic Levels of the UART Interface
Table 8: Pin Definition of the UART Interfaces