Ok, i've bought a gsm900 in alexan, and what i bought was a gsm shield thinking that it is really just the same only that shield can be placed directly in an arduino.
The problem is that, im trying to do a computer system that utilizes gsm module to automatically send sms notifs, but the gsm shield does not have rs 232 port like some of the gsm module available in the internet. And Im thinking would it be possible to connect my gsm shield to an arduino then connect the arduino to the pc, would the at commands coming from my computer system be able to pass through the arduino and send it to the gsm? Or if it is possible how should i do the programming? Im using visual studio 2012 and c# as my language.
Ps. My gsm shield have small male pins namely rx tx gnd and i cant remember the other one, (my gsm shield was with my friend at this time). And i have read that rs 232 are composed of that pins. Correct me if im wrong, can i just buy/creata/modify an rs 232 cable so it can be connected through those pins? I still have very limited knowloedge bout gsm.
Thanks!
Best Answer
Either buy (or build) an RS232 to TTL UART converter. You can use something like the MAX232 to do that if you don't want to buy one. There are other options for RS232 to TTL, such as this Simple RS232 Converter which uses a couple of transistors arranged as:
Image Source
Or if you are connecting it to a computer, you can either buy (or build) a USB to TTL UART converter (e.g. FT232RL) and use that to connect to the module. Or if you are using an Arduino, you can program the ATMega to act as a simple bridge between the GSM UART pins and the USB-UART converter on the Arduino board.