I hope somebody can help to this Problem:
In my application the SL8090 is powerd up at some times and waits for incoming SMS. After that it is powered down again.
My question is:
Is there any possibility to check if there is no SMS available or if the time for waiting is not long enougth?
All Actions are done with AT commands.
Thank you for help.
Andreas
That would, indeed, be great - but, unfortunately, it is not possible.
Correct, SMS reception is passive and all depends on network.
Normally network should send the SMS to module once it registers, so I think keeping the module online for 5-10sec is long enough.
Please also make use of +CNMI for SMS unsolicited notification and +CPMS/+CMGL to check if there are new SMS received and stored by module.
Hope this helps.
Thank you for your answers.
I already use +CNMI and +CMGL to check for new SMS. It works fine.
I have seen that the modem has to be powerd on for about 2 minutes to be sure to get a SMS from my network.
Thank’s again.
Andreas
Normally, yes - but there is no guatantee 
I have seen text messages delayed several hours…
Again, it should generally be enough - but there is no guatantee
If it really matters to you, then you will have to design some higher-level confirmation mechanism into your application…
You might be be able to negotiate a specific service level with a specialist provider - for a fee, of course…
See https://forum.sierrawireless.com/t/cmti-not-received-if-sms-send-while-fx100-is-power-down/7332/12 for other causes of delayed SMS delivery…