The question is that holding a GPRS conection in transparent mode we need to check if a new SMS is coming. Now, we are sending +++ and switching to command mode, reading the mailbox and return to transparent mode. But this is not good for us because needs to repeat the operation frecuently to check every 10 seconds.
But isn’t this a Radio/Network issue? I don’t believe that the Q2686 can do simultaneous DATA and VOICE (i.e. SMS) bearers.
However, I do know that the Q2686 will park a GPRS session when an inbound VOICE session is established, and re-establish the GPRS session once the VOICE session has ended.
Maybe the SMS behaves the same way? I would look at writing an OpenAT app that registers for SMS events and handles the GPRS traffic. Then the app could use the CMUX interface to pass DATA down one virtual serial port, and provide SMS events down another…
also, sms is not necessarily a voice service. (my simcard doesn’t have voice service but can send and receive sms)
and in my phone i can choose which bearer to use when sending / receiving sms.
I don’t know about other countries, but here in Denmark, our operators clearly state that they bill you with the same amount no matter if you send the SMS over GPRS or GSM.
The “CMUX” driver for PC is available in the Download section of the Wavecom web site (Drivers, CMUX Driver).
Under Win CE, there is a Radio Interface Layer (RIL) which offers an easy access (using APIs) to all the features of the GSM/GPRS/3G modem (or module).
The RIL also uses MUX in order to be able to run AT command on a channel while a data transfer is running on another channel.
(e.g. this allows Win CE to receive an SMS while browsing the web).
Wavecom provides RIL/MUX drivers for:
Windows CE 6.0
Windows Mobile 6.x
Windows Mobile 5.x
Click [here] to obtain RIL/MUX drivers for Embedded Windows® (link also available in the Download section, Drivers, RIL Driver).