MMS Download over GPRS
The reception of an MMS message has two parts. First an
SMS arrives to the
modem, that contains the URL of the MMS message. The second phase is the
MMS download. In the second phase the modem opens a GPRS connection and
it downloads the MMS message from the MMSC. In this guide we give you
information on how you can use two modems to speed up the process.
If you want to receive MMS messages it is a good idea to use two modems.
One modem should be connected to Ozeki NG SMS gateway and would be used for
receiving SMS messages. The second modem should be connected to the GPRS
network and would be used for receiving MMS messages.
With this configuration you can speed up MMS reception, because the second
modem, will always stay connected to the GPRS network and will download your
MMS messages as soon as the MMS indication SMS message arrives to the first
modem. This way you save the time it takes to setup a GPRS connection for MMS
The quick start guide explains
how you can configure Ozeki NG SMS Gateway
to receive SMS messages. In the next section I explain how you can configure the
second modem, that will always stay connected to the GPRS network.
To configure your GPRS modem first you have to specify the GPRS access point
for MMS download in the modem configuration in Windows. This
can be done in the Windows Control Panel as shown in Figure 1 and Figure 2.
Figure 1 - Open the modem preferences form.
Figure 2 - Configure the GPRS apn
The GPRS APN can be configure using the AT+CGDCONT=1,IP,"apnname" modem
The next step is to setup a windows dialup connection using this modem. In
the dialup connection you should use the GPRS activation number as the dial
string. This is usually "*99***1#" (Figure 3).
Figure 3 - GRPS dial string
Once your dialup connection is specified, you should dial it. This will
connect you to the GPRS network and will assign an IP address to your connection.
The final step is to configure the IP routing table to make sure the MMS
download traffic goes through the GPRS connection. You can use a windows
command shell (cmd.exe) to perform this configuration as described in
Figure 4 - Windows routing configuration.
After this is done you can configure Ozeki NG SMS Gateway not to use this modem.
If you do not want the SMS gateway use this modem then you can check the
Do not use this modem for MMS transfers option in Network Settings
section of MMS settings tab. By default the SMS gateway uses the
existing Internet connection for MMS transfers instead of a new one (Figure 5).
Figure 5 - Configure Ozeki NG SMS Gateway
GSM modem debugging