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NowSMS Support Forums ⬆ NowSMS Support - MMS & Advanced Issues ⬆ Archive through February 20, 2004 ⬆ |
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| Author | Message | |||
| Joakim Westin |
Hi! I'm about to pilot a setup where we receive MMS using NowSMS. When reading the documentation I read that the handset should not support MMS since it would then process the MMS before NowSMS can do anything with it. I have not been able to find many phones that supports GPRS but not MMS. Can you please advise? Kind regards, Joakim Westin | |||
| Bryce Norwood - NowSMS Support |
Joakim, We're updating that text in the documentation, as it is quite confusing. Basically, you want to avoid using a phone as the modem in such a configuration, as you're unlikely to find a GPRS handset that doesn't support MMS. I'm sure there are some out there somewhere, but whether or not they also function reliably as a modem would then be a question. You'll want to get a dedicated GSM/GPRS modem device. The Siemens MC35 seems to be a good choice for an external modem. I've been using a Sierra Wireless Aircard 750 myself, which is a PC card ... it has a benefit that it can do GPRS and SMS simultaneously which an external modem can't (and most other PC cards can't either). Anyone else have any suggestions? -bn | |||
| Will Neale |
Further to Bryce's previous email, why can an external modem not manage simultaneous GPRS and SMS when a PC Card can? | |||
| Bryce Norwood - NowSMS Support |
Will, That's a good question, I should explain that some. Basically, an external modem has to connect to the PC over a serial (or USB) connection. When sending/receiving SMS messages via the modem, the modem is in "AT command" mode, and an application sends/receives commands to interact with the modem (such as sending/receiving SMS messages). In order to initiate a GPRS connection, the phone issues an AT command similar to the type of command that is used with a conventional modem to dial into an ISP. When a connection is established, the modem enters an on-line state where it acts as a transparent pipe for communication between the PC and the server to which it is connecting. As long as the modem is in this on-line state, it is no longer possible to send AT commands to interact with the modem. So the on-line state must be exited before AT commands can again be issued. (Theoretically, there might be a way to send an escape sequence to the modem to temporarily re-enter the AT command mode ... but there is no way to do this if dial-up networking is managing the connection.) A PC Card is not limited to the serial type of connection, although most seem to use an interface that emulates this type of connection. In the case of the Sierra Wireless Aircard 750, it has a separate network driver that manages the GPRS connection, while the AT command state is still accessible over the serial link. A clever external modem developer could implement a protocol and write network drivers to do the same type of thing, but it would be considerably more complex. There would have to be an emulated COM port for sending the AT commands to the device while the device is in an on-line state ... and I just can't imagine an external modem manufacturer taking the time to develop such a driver. In fact, I haven't seen any PC card drivers doing this other than the Sierra Wireless Aircard. The only way to get around this mode switching issue with an external modem is to have multiple modems. The only catch is that your operator might not allow a GPRS modem to fetch an MMS message URL that was originally sent to a different a modem. That is something that you would need to test with your specific operator connection. -bn | |||
| Joakim Westin |
Thanks for the clarification re modems. I'll try to get my hands on the Sierra Wireless so that I can do SMS/GPRS simultaneously. /Joakim | |||
| Joakim Westin |
Would the Sony Ericsson GC75 GPRS PC-card modem work? It is more well supported here in Sweden ;-) Cheers, Joakim | |||
| Bryce Norwood - NowSMS Support |
Joakim, I haven't had any specific experience with the GC75. I searched through our tech support archives, and I've seen multiple instances of customers that were using this modem with NowSMS. And I didn't see any reports of unusual problems. I suspect that it does not have a driver like the Sierra Wireless Aircard which enable simultaneous support. But it otherwise should be fine. I did find technical specifications for the device on-line, and it indicated that it supported the various specifications that we require (specifically ETSI GSM 07.05 for sending/receiving SMS, and ETSI GSM 07.07 for GPRS related functions). So it looks fine, as long as you are in Sweden.  If you have any thoughts about moving to Finland, I hesitate on recommending the Nokia D211, as that device doesn't support the AT command set for receiving SMS ... only sending ... which is somewhat limiting. -bn | |||
| Joakim Westin |
Thanks for all your support. I've ordered a Sierra Wireless card (I had a hard time finding a distributor/dealer - probably because Sweden is Ericsson territory ;-)) and it is waiting at the post office. Will try as soon as I can. Cheers, Joakim | |||
| sachin Unregistered guest |
Can anybody suggest me how to develop protocol suit for sending and receiving SMS on nokia mobile? I wanted to know packet format and related details for the same on serial communication | |||
| Bryce Norwood - NowSMS Support Board Administrator Username: Bryce Post Number: 1579 Registered: 10-2002 |
The specifications are published by ETSI (www.etsi.org). The relevant specification is ETSI GSM 07.05 (which documents the AT command set). That document will also cross reference some other ETSI specifications, but it's a good place to get started. And of course, since you're posting this in the Now SMS/MMS Gateway support forum, please feel free to visit the home page of this web site (http://support.nowsms.com/discus), and download the eval version of the Now SMS/MMS Gateway, which will allow you to send/receive SMS messages via an HTTP interface through a GSM modem or other SMSC related protocols. | |||
