Unit A is one of these: https://www.itead.cc/wireless/gsm-gprs- ... -v2-0.html.
Unit B is one of these: https://www.waveshare.com/product/modul ... ss-hat.htm
Using both a Pi model B+ and a Pi Zero, I can successfully turn on Unit A at boot by the addition of these commands to /etc/rc.local:
Code: Select all
echo 17 > /sys/class/gpio/export echo out > /sys/class/gpio/gpio17/direction echo 1 > /sys/class/gpio/gpio17/value