Serial communication ESP32 with 3G SARA ublox 201

I'm trying to make communication between my ESP32-WROOM-32D board and the modem UBLOCX SARA U201
I saw that there is an Arduino library that supports this modem (tinyGSM) and I uploaded an example sketch.

Wiring between two board are these:
RX1 --> RX
TX1 --> TX
CTS1 --> CTS
RTS1 --> RTS

link of datasheets boards:

looking from serial monitor esp doesn't see the modem!!

We have done a further test:
have connected the modem directly pc with usb cable.
we made a further test: we connected the board via USB cable and through a serial reading program we saw that the modem actually works!!

have anyone connected successfully the modem to a bord? can anyone help please?

tinygsm_u201.ino (7.65 KB)

I dont know the 3GSARA Click board, if there are specific issue with it, ask Mikroelectronica, they sell it, so might be expected to support it.

You have RX1 on the ESP32 and RX on the Click board connected, and TX1 to TX.

You would normally connect TX - RX etc.

The first issue I see with the connection is using the flash programing pins for serial inputs. Unless you got a very good understanding of the ESP32 and coding for it, forget using the first 3 pins to either side of the ESP32 USB connector.

You'll want to use the GPIO_NUM_16 and GPIO_NUM_17.

Get a better pinout diagram.

Please post you well formatted code in code tags so we can see it without having to download it.

Follow a tutorial on using the ESP32 hardware serial ports, use the words "esp32 hardware serial port" to find one.

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