Problems with MultiTech Multimodem GPRS

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SMS & MMS Technical Forum » NowSMS Support - SMS Issues (Product Support Only) » Archive through June 02, 2006 » Problems with MultiTech Multimodem GPRS « Previous || Next »
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Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5760
Registered: 10-2002
Posted on Friday, March 31, 2006 - 04:23 pm:   

Hi ... Shane?

I don't know if our discussion board software somehow choked on your message, or what happened.

I've never seen this problem with the discussion board software before. I see a subject but no message.

Can you please repost the details regarding your problem?

-bn
Shane Dewing
New member
Username: Shanedewing

Post Number: 9
Registered: 01-2006
Posted on Friday, March 31, 2006 - 04:55 pm:   

Bryce, I have tried to post the message 3 times now - appears to fail each time. I will try without uploading the files to see if that works. Alternatively, is there an email address to which I send the post?

Regards,
Shane
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5774
Registered: 10-2002
Posted on Monday, April 03, 2006 - 04:40 pm:   

Hi Shane,

Maybe it's an issue if you upload a file without also including some text. Hmm...

Since the HyperTerminal test works ok, I'm wondering if you're encountering a problem that is specific to trying to send the SMS over GPRS.

Try setting "SMS Access" to "GSM", and see if that makes a difference.

-bn

Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5775
Registered: 10-2002
Posted on Monday, April 03, 2006 - 04:42 pm:   

Now that is weird ... your message was here ... I could view it.

Then I posted my reply, and your message that includes all of the details is gone. I don't understand this ...

Shane Dewing
New member
Username: Shanedewing

Post Number: 11
Registered: 01-2006
Posted on Monday, April 03, 2006 - 05:09 pm:   

Hi Bryce,

There must be a jinx on me!

Setting the SMS Access to GSM seems to have fixed the issue. NowSMS is delivering and receiving both text and binary SMS's fine via the Multimodem now.

However, I have seen many posts on this board where customers are using the Multimodem in GPRS mode without any issues, and I do need to maximize the SMS throughput as much as possible. When I put the SIM card that is in the modem now into a handset like a Nokia 7250i, and set the delivery method to GPRS it works fine, so I know that it's not a problem with the Carrier or the SIM. Any idea what could be wrong with the modem? I have been on support calls with Multitech, and as far as they are concerened the modem is operating OK.

Any help or ideas are much appreciated.

Kind regards,
Shane
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5784
Registered: 10-2002
Posted on Tuesday, April 04, 2006 - 08:22 pm:   

Hi Shane,

A mobile phone configured for SMS over GPRS might be better at falling back to GSM if it encounters an error.

My suggestion would be to try hooking the 7250i up as a GSM modem for NowSMS ... and do some limited speed tests to see if you see a difference with NowSMS set to GPRS vs. GSM for the SMS sending.

If you don't see a speed difference, then it is probably an issue that whatever error is occurring, the phone is better at falling back to GSM when it encounters an error than the modem is.

If you do see a speed difference ... then that is a puzzler. We did encounter some issues early on when we first tested the Multitech where we had to add some extra GPRS initialisation commands to get it to work with SMS over GPRS. However, that was almost 2 years ago ... and without the extra initialisation commands it was just slower, it didn't return errors.

So if you do see a speed difference on tests with the 7250i, then I'll do some more research to see what we might be able to try. (Unfortunately, I'm going to have only limited participation out here until April 17, so it might take me longer than unusual to do this research.)

If you don't see a speed difference, then it may be an issue that the carrier doesn't support SMS over GPRS accross their entire network. For example, a year and a half or so ago, we had someone doing some tests who found that T-Mobile in New York City did not support SMS over GPRS, but T-Mobile in Baltimore did. I've heard similar stories about Cingular where it seems to vary by region. (I mention this, because I think you said in the disappearing post that you were in the US on one of these 2 operators.)

-bn
Shane Dewing
New member
Username: Shanedewing

Post Number: 12
Registered: 01-2006
Posted on Wednesday, April 05, 2006 - 03:10 am:   

Hi Bryce,

I tested the Nokia 7250i with the same SIM card (T-mobile, USA) and NowSMS set to use GPRS. The handset reliably delivered 10 (80 character) SMS's in 60 seconds.

When I place the SIM card in the Multitech (and obviously set NowSMS to use GSM mode), the modem delivered 6 (80 character) SMS's in 60 seconds.

Do you by any chance remember the additional initialization strings that you sent the Multitech to get it to use GPRS for SMS?

Thanks for all your help with this. I need to get the Multitech, or some other GSM modem, to deliver higher than 15 SMS's per minute.

Regards,
Shane
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5815
Registered: 10-2002
Posted on Thursday, April 20, 2006 - 03:14 pm:   

Shane,

Sorry for the delay. 10 in 60 seconds sounds like the handset isn't getting SMS over GPRS either.

Let's try this. Edit SMSGW.INI, and under the [Modem - Multitech...] header, add:

CommandPostInit1=AT+CGSMS=0

This is going to tell the modem that it can only use GPRS for sending, it cannot fallback to GSM.

Try this setting with both devices. Do the messages go out, or are there now errors?

The AT command that we added before is AT+CGATT=1 (attach to GPRS). It is not shown in the logs, but we are sending it if SMS over GPRS is selected.

My suspicion is that for whatever reason, in your region, T-Mobile is not supporting SMS over GPRS.

-bn
Shane Dewing
New member
Username: Shanedewing

Post Number: 13
Registered: 01-2006
Posted on Thursday, April 20, 2006 - 04:26 pm:   

Hi Bryce,

I tried AT+CGSMS=0 and AT+CGATT=1 on the Multitech, and the sends failed each time, first with +CMS ERROR:500 and then with +CMS ERROR:1

With the SIM card in the Nokia 7250i, and with AT+CGSMS=0, SMS's are sent/received with no errors.

So it does point back to the Multitech not supporting SMS over GPRS correctly.

I will be doing some more load tests with the 7250i today to see if I can get it above 10 per minute.

Kind regards,
Shane Dewing
Frantz Pierre-Louis
New member
Username: Peteranz

Post Number: 1
Registered: 05-2006
Posted on Friday, May 05, 2006 - 12:40 pm:   

Hi Bryce,

I've seen on this discusssion board that multitech is usefull with Now sms. I've encounter some errors when trying to send SMS. Please read the files attached to see what's wrong and help me solve the problem.(I have a Multitech gsm-gprs 850- 1900).
application/octet-streamlog files
SMSOUT-20060504.LOG (11.1 k)
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5907
Registered: 10-2002
Posted on Monday, May 08, 2006 - 07:28 pm:   

Hi,

These type of setup issues can be difficult to diagnose, because "CMS ERROR 500" is defined as an "unknown error".

Usually, when I encounter this error, it means that the modem doesn't have a signal.

But it could also be an issue of the modem defaulting to trying to send SMS over GPRS, but the operator not supporting it (or having it partially implemented but misconfigured). Under "Properties" for the modem in the "SMSC" list, try changing "SMS Access" to "GSM".

If that doesn't resolve the issue, then let's confirm that it has a signal.

Try connecting to the modem with HyperTerminal, and issue the command AT+CGREG? ... you should get a response like this:

+CGREG: 0,1

If the second number is 1, the device is connected to its home operator. If that second number is 5, the device is connected to a roaming operator. If the second number is some other value (like 0), it is not finding an operator.

Next, issue the command AT+COPS=? ... it takes a few seconds to come back ... basically this will list the operators that the phone sees (like the view available networks option on most mobile phones).

-bn
Frantz Pierre-Louis
New member
Username: Peteranz

Post Number: 2
Registered: 05-2006
Posted on Tuesday, May 09, 2006 - 03:13 pm:   

Hi Bryce,

I tried the At commands suggest at+cgreg?. values returned:at+cgreg?
+CGREG: 0,0

OK

AT+COPS?
+COPS: 1,2,37201

OK
AT+COPS=?
+COPS: (2,"Voila","Voila","37201")

OK

Today Now sms send an SMS and fall down again.

2006-05-09 10:57:37,44609D30.req,127.0.0.1,4540865,OK -- MultiTech Systems USB GSM_GPRS Wireless Modem,DCS=10;Text="TEST DU MODEM"

Please tell me: is this a problem with the modem or are there some commands to troubleshout it.
application/octet-stream
SMSDEBUG.LOG (0.1 k)
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5915
Registered: 10-2002
Posted on Tuesday, May 09, 2006 - 04:10 pm:   

Hi Frantz,

I made a typo above. I meant type to AT+CREG, but instead I typed AT+CGREG (in fact, I did it again here before I corrected it ... I've got GPRS on the brain because of the earlier bits of this thread).

The fact that AT+COPS is showing your operator suggests that you are connected ... but I'm still suspecting that your signal is low. I guess I wasn't clear on that above ... but usually when I see this "CMS ERROR 500", it means that the modem has low or no signal. Especially, if you are seeing this error intermittently, this is what I would suspect.

Try changing the location of the modem to see if you can get a better signal.

Did you try my suggestion of changing "SMS Access" to "GSM"?

Unfortunately, your SMSDEBUG.LOG is empty, so it doesn't tell me anything. (This log is recreated each time the service is restarted, and it also rolls over to a new file each day.)

-bn
Frantz Pierre-Louis
New member
Username: Peteranz

Post Number: 3
Registered: 05-2006
Posted on Wednesday, May 10, 2006 - 11:55 am:   

Hi Bryce,

I think you're right about position. I was able to send SMS twice. That means the modem ran normally.

However, Do you think I'll need an antenna to increase the signal? If so I'd prefer using an other modem because I am using this one to present a new service. I don't want to have trouble during the presentation. Would you please recommend another USB modem.

PS. I made the change SMS acces to GSM.
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5925
Registered: 10-2002
Posted on Thursday, May 11, 2006 - 02:24 pm:   

It's hard to say whether or not you need an antenna to increase the signal. I have a Multitech GPRS modem (serial model as opposed to USB) in my office. My mobile phone signal is relatively weak in the office (1 to 2 bars), but I haven't seen a problem with the modem. I'm just using the stub antenna that shipped with the modem.

I'm not sure that another modem without an external antenna would fare any better. Among PC cards (if you're using it for a presentation on a laptop), I like the Sierra Wireless Aircards, in part because that (sometimes annoying) external antenna is quite good at picking up a strong signal.

-bn

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