Hi there..
I want to try something but i want to ask first to those that have experience in it.
This is the case: for example, I am a boss.. (hopefully:)). Every employee has its own RF ID. For every employee that will login in my device. (Attendance Monitoring). The sim900d will send text message to my phone. Their names and phone number are saved in the SD card. File format is ".TEXT". Actually the concept is very simple.
But how about if there will be a mass entry (mass swiping) in the device. say a thousand 
, what do you think will happen? Will the device hang? or my gsm device fails? What can you suggest? I think a delay() is may solve it but this may take time...
Please help, i cant afford to loose my components as of now. No extra budget for now :')
Advance Thanks to all....