SIM900B not sent to SMS!

[diepvu1805]

Hi all,
I am using SIM900B V1.02. I try to send sms but can not. I use AT+CSQ to check the signal, it respond: +CSQ 0,0.
when I using the multimeter to check the resistance between signal pad and gnd pad => result: 0Ohm.
I don't understand that.
please, help me.
Thank,

 

[Gapoo]

Hi
+CSQ 0,0 means that modem is not getting the signals.
The antenna and terminal will show short on meter since resistance is too low.
Check the connections which are between SIM Holder and Modem. It is a common mistake that sim connections are not correct.
What message do you receive when you power up SIM900 ?

Thanks.
Regards.
Gapoo.

 

[diepvu1805]

Thank you,
I sent to the sms successful. Because the connection between RF cable and connector of antenna not good.