Trying to build a small GSM library

@user7143 yeap thats the route you should go down in my opinion.

Typically you will take the response from the on.data, build up a buffer to get a complete command and then check the command to see if it has the required response.

I was part the way implementing that and got confused over how I wanted to go about it. You will see in my original code I had an answer variable which stored the expected response agains the sent command. Note. The answer is not always OK nor is it always the expected answer.

I was hoping to do the check agains the response buffer to see if I got what I wanted in return. If I didnt I would just raise and error and shutdown the module.

There is also the scenario where you have slow response or no initial response. This is why I had the timer implemented into the send command function. This meant that I could repeatedly run the command every few seconds if I didnt get an answer back from the module. There is also the scenario where the command times out, so how long do you want to keep sending a command or waiting for a response until you decide the module is either dead or unresponsive? You can potentially end up in a loop.

As you can see there are a few things to consider and I think I rushed in to it at first without splitting all of the problems down and building out the solution. In my confusion I created quite a mess which I'm now working on to fix. Would be good if you could share your code though might help me get a bit further on my work :)