Main Uart Port - Quectel NB-IoT Module Series Hardware Design

Debug UART Port:

TXD_DBG: Send data to RXD of DTE.

RXD_DBG: Receive data from TXD of DTE.
Auxiliary UART Port:

TXD_AUX: Send data to the RXD of DTE.

RXD_AUX: Receive data from the TXD of DTE.
Ringing Signal:

RI: Ring indicator (when there is a SMS or URC output, the module will inform DTE with the RI* pin).
For more details, please refer to Chapter 3.12.
Table 9: Pin Definition of UART Interfaces
Interface

Main UART Port

Debug UART Port
Auxiliary UART Port
Ringing Signal
NOTE
"*" means under development.
3.8.1. Main UART Port
The main UART port is used for AT command communication and data transmission. It can also be used
for firmware upgrading. The default baud rate is 115200bps.
The figure below is a schematic diagram of the connection between DCE (the module) and DTE.
BC66_Hardware_Design
Pin Name Pin No.
TXD 17
RXD 18
RXD_DBG 38
TXD_DBG 39
RXD_AUX 28
TXD_AUX 29
RI* 20
NB-IoT Module Series
BC66 Hardware Design
Description Comment
Transmit data
Receive data
Receive data
Transmit data 1.8V power domain
Receive data
Transmit data
Ring indicator
25 / 50