Receive SMS during GPRS / TCP


Our device connects with TCP socket over GPRS to server and periodically sends packets of ~50bytes. The application can receive SMSes to change the parameters etc. So far the packet sending period was always greater than 10 seconds and everything worked OK. When the period was shortened to 1 second, the SMSes were not received anymore. Changing period back to 30 seconds and the missing SMS was sooner or later delivered.

Actually the margin is 5 seconds. Anything shorter, no received SMS. Also, when dial-in voice call with fast period packets, unknown female voice informs ‘the number is not available’. With period > 5 seconds, the incoming rings are detected.

The device is Fastrack Supreme 10 and runs on R74a.

Can this be my provider, OS (WIP), or am I missing some setup?


May be this could be because of the fact that when you shorten the packet sending period and you send data across your shift to the AT command mode is for a very brief period(which might not be enough for receiving the indications).As a suggestion try using CMUX so that on one channel you can be on data mode while on the other you get the notifications.


That will be a network announcement.

Are you using an Open-AT application, or AT commands from an external device?