
I am using the Cell with an Arduino MKR1000, connected to hardware Serial2. As soon as the UART communication starts working, all is fine, but the initial startup has an issue.
After resetting/powering the Arduino, a 100ms LOW signal is put to PO. Hence the Cell restarts and is able to establish a 3G connection, as I can see from the LED.
But serial communications on the UART is possible only once in a while - it may work immediately after power up, may take several seconds to minutes to finally get up or never start at all. I see all three schemes repeatedly, with the comms failing more often.
Serial speed was set to Auto (+ZBITRATE=1, then +ZBITRATE=S), with the Arduino communicating at 9600 baud at the moment.
It is not reliable enough for me to use, so what would you suggest doing?