LoNet 808 not responding

Dear all,
I bought a LoNet 808 breakout board, but I cannot talk with it.

I soldered a header on the holes of the LoNet 808.
I connected the LoNet 808 to my laptop through a USB to Serial adapter (GND to GND, 3.3V to VIO, TX to RX and vice versa).
I connected the GSM and GPS antennas and a 3.7 battery to the LoNet 808.
I powered on the module using the poweron button on it: the green led is on and the red led is blinking.

Now, I open miniterm.py (on Linx) with the following line:
$ miniterm.py -b 115200 -p /dev/ttyUSB0 -e -D -D -D --cr --xonxoff
and test the communication by issuing an “AT” command. The leds on the USB to serial adapter are flashing, so the bytes are sent, but the module is not responding.

What am I doing wrong?

I also tried without the --xonxoff (I read that by default, the SIM808 has hardware control on, is this true?) and without the --cr (should I send a \r\n or just \r? Docs are not clear about this).

Just to be sure, I also tested using an Arduino as “bridge” between my laptop and the LoNet808 (there is a sketch here seeedstudio.com/wiki/LoNet_8 … S_Breakout): no luck again :frowning: