I have an LTE module (quectel bg95) that gets AT commands from a host esp32 (esp32-wroom-32ue) via a UART connection. And in the ESP documentation AT manual to send AT commands I should connect: RXD, TXD, CTS, RTS. But in the module's hardware integration manual it shows many more connections shown below. Which lines do I need to connect to send AT commands?
Edit... Datasheet info that may help decide which connections are necessary. The the only other info in the datasheet I could find regarding the main UART connection (for AT commands) is as follows:
The module provides three UART interfaces: the main UART, debug UART and the GNSS UART interfaces. The main UART interface supports 9600, 19200, 38400, 57600, 115200, 230400, 460800 and 921600 bps baud rates, and the default is 115200 bps. It is used for data transmission and AT command communication, and supports RTS and CTS hardware flow control. The default frame format is 8N1 (8 data bits, no parity, 1 stop bit). The debug UART interface supports a fixed baud rate of 115200 bps, and is used for software debugging and log output. The GNSS UART interface supports 115200 bps baud rate by default, and is used for GNSS data and NMEA sentences output.
So the datasheet specifically mentions functions of RXD, TXD, CTS, RTS but I am not seeing anything for DTR, DCD, or RI. What are these? datasheet