PH8 and freeze on SMS | Thales IoT Developer Community
May 28, 2014 - 2:20pm, 3318 views
It happens to me that sending several SMS to the modem, while it is engaged in IP activities (like Internet downloading), it stops to work for a while (average 1 minute).
In the monitor I don't see sometimes +CMTI command, in other cases I see it but nothing more happens on the modem.
Does it happen to somebody?
Thanks and Regards
May 28 2014 - 4:09pm
Hello,
you can check if you're registered in 3G or 2G using AT^SMONI command. It seems that you're probably in 2G network. The most important here is Network Operation Mode - most GSM network are NOM2 network. In this networks the same paging channel (PCH) is used to monitor circuit switched and packet switched services. In consequence SMS cannot be received when a GPRS connection is active. Only NOM1 network allows to receive SMS or call during active GPRS transmission.
It's important to mention that active transmission means data are send exactly in this time. When no data is send network can deliver SMS. Some longer brake in transmission are necesary to be able to receive SMS or incoming voice call. The break is normal behavior as GSM system need some time to free signaling resources used by GPRS to be used for SMS delivery.
Hope this clarification helped.
Regards
Jedrzej
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