I do have some doubts about the communication of the SIM900 GSM module with the PC. By default the GSM module has the RS232 connection to interface with PC.
But my PC has only USB connection . So do I really need a USB to RS232 connector for interacting with PC , something like
CAN I COMMUNICATE the SIM900 module from the PC using the TTL by using a USB to TTL converter and connected to the Rx/Tx pin of the GSM module using something like this?