SMS over GPRS - Sierra AC750

SMS over GPRS - Sierra AC750 SearchSearch
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ashot shahbazian
New member
Username: Animatele

Post Number: 12
Registered: 06-2004
Posted on Wednesday, June 16, 2004 - 11:46 pm:   

Bryce

I tried it again, no luck. Here's what I did:

1. checked SMS over GPRS in modem properties
2. tried sending a message with Sierra Watcher running and "connected" and with Watcher disabled completely
3. Tried with and without CommandPostInit1=AT+CGSMS=0 command in smsgw.ini

All I got was +cms error 500. Simcard inserted in an ordinary phone does send SMS over GPRS (very slow, however.)

When I just press "Connect" in Watcher the counter shows 0 bytes sent and received. Attempting to send a message via GPRS does not change the values, which makes me think that I'm not doing it properly with NowSMS.

With Watcher "connected" I can browse Internet, so the card itself is functioning. Sending SMS via GSM works fine with the same modem/sim.

Any ideas?
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 2870
Registered: 10-2002
Posted on Thursday, June 17, 2004 - 08:49 pm:   

Ashot,

I suspect the carrier doesn't support SMS over GPRS. As you mention, in the ordinary phone, when you configure it for SMS over GPRS, it is very slow.

Generally speaking, when you configure a device for SMS over GPRS (or enable the setting in NowSMS), the device will fall back to SMS over GSM if the appropriate infrastructure for SMS over GPRS is not present. (You run into issues in some environments where the infrastructure is present, but is not properly configured or enabled.)

That AT+CGSMS=0 tells the modem not to fall back to GSM.

So it looks to me like the operator doesn't have this support.

-bn
ashot shahbazian
New member
Username: Animatele

Post Number: 14
Registered: 06-2004
Posted on Thursday, June 17, 2004 - 09:00 pm:   

They told me they do. I'll find out maybe it's an extra feature that needs to be activated.

Then again, how would you explain that the modem isn't sending a single byte while attempting to send SMS over GPRS. I suppose it should at least try to query something on carrier's end to realise the feature is off.

I came across your explanation how to force the AC750 stay connected via its "network driver" while Watcher's off (inserting-removing procedure.) Perhaps this is what's to be done?
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 2893
Registered: 10-2002
Posted on Wednesday, June 23, 2004 - 05:21 pm:   

Ashot,

The way that SMS over GPRS works happens at a lower level than a PDP context activation where the device connects to an APN and gets assigned an IP address (which is what we normally think of as a GPRS connection).

The counters that you mention only apply to IP traffic. SMS over GPRS is all lower level datagram traffic, below the IP layer.

The device does have to perform a GPRS attach (which it should do automatically) in order to use SMS over GPRS. However, it doesn't have to perform a context activation which is where the IP layer is activated.

-bn


ashot shahbazian
New member
Username: Animatele

Post Number: 16
Registered: 06-2004
Posted on Thursday, June 24, 2004 - 08:05 am:   

Okay Bryce, thanks for clarifying!