Hello everyone, my sim900 is not connecting to network. It is connected to external power supply, the SIM on it is the SIM that i usually use in my phone, so it works. My country supports 2G network.
When i power up my SIM900 module, it is blinking once a second, so i know that module is working but can not connect to network.
What can be possible problems?
Thanx for helping.
Hi, what is the power supply that you're using?
it is bench power supply which is set to 5V 3A
Can you get any diagnostic information from the device using AT commands?
yes, when i send AT it repeats OK, but when i send AT + CREG? it repeats 0,0 . Meand it is not connected to network
Are there more tests you can do with the AT commands? For example, verify the SIM?
What about hardware? Is your antenna connected? Is there adequate network service in the test location?
antenna is connected and yes it verifys the SIM, also there is network service. when i put sim to my phone it connects to network normally
Okay, it's likely a code problem then. Probably, you have to make some AT requests to make it connect... maybe you have the wrong ones, or some step is missing..
What is the pattern of the Network LED blinking? If it is registered to the network, it should blink after every 3 seconds.
Problem is solved. I am typing the problem so it can help to somebody. The IMEI code typed on the SIM module is not the actual IMEI of the module. You can check IMEI code of module with AT+SIMEI? . So you can register it to the network,