Hello! i am new in the arduino world. Ι am using SIM900 Quad Band GSM GPRS Shield for phone calls. It was working perfectly well, but suddenly it stops the connections with network. The red led flashing every second instead every 3 seconds until now I tried multiple sim cards which i also tried …

SIM900 Quad Band GSM GPRS Shield NETWORK PROBLEM

ieee488 April 11, 2018, 10:17pm 2

If nothing's changed - that's an important if - it may be your cellular company.

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