Sim900 Seeed Studio Library

I have been looking for a asynchronous library for my GSM module for a long time and the best I could find so far is the library developed by Seeed Studio. HERE

My GSM Module HERE

According to the documentation THIS library can be used with AltSoftserial. I am no expert but I assume that the softwareserial call’s inside the library must be changed to Altsoftserial.

I am currently reading an xbee aswell via Hardware serial. How can the library be modified to use hardwareserial instead?

The GSM module will be in production on a Mega. Currently testing on UNO.

Unfortunately, it looks like you're correct. It's unfortunate that the authors of the GPRS_SIM900 library didn't write it so that you could pass any Stream object to the library to be used for communication with the SIM900. That would have allowed it to be used with a spare hardware serial port (which you likely have on your Mega) or your preference of software serial libraries without any need to modify the library.

I tried the last couple of hours trying to change all reference's in the library for softwareserial to altsoftserial, using the define statements in the altsoftserial library to define the pins and then using that to initialize the serial port.
But I get nothing back after I send AT.

Like I said, I am no export so most probably I did not do it correctly.

The main reason I wanted to change to altsoft was because my xbee serial and GSM serial seems to crash at somepoint. So I will be applying the suggestion at the bottom of the altsoft website.

My hardware serial was 57600 and GSM set at 19200. I will test the GSM with 57600.
I do currently have code that permits only one serial port to be checked at a time.