Trying to build a small GSM library

I am also trying same test. As well as serial setup I see a few other things that I dont quite understand. Does espruino have a blocking timeout command? when setting c0 high for 2 seconds using digitalPulse does not block I tried using setTimeout(function(){},2000); after digitalPulse, the code continues and sends AT commands before the GSM unit turns on.

I am struggling to understand how the responseCallback routine works.

I am finding it really interesting to read and try to debug code. It gives a much better understanding of the way that Javascript works.