Prepare the SIM card
Select the SIM card
The SIM card you use with your GSM modem should be suitable for your application. A prepaid SIM card with a low cost per SMS might be a good choice if you want to send an SMS mailing to your customers or if you mainly want to receive SMS messages. If you use the software to forward important alert messages, a mobile phone plan with a higher price per SMS might be the better choice.
SMS Central number
Sending messages with the GSM modem is only possible with the proper SMS Central number. Diafaan SMS Server will read the SMSC number for your network automatically from the SIM card when the GSM modem is initialized. It is not always possible however to detect the right SMSC number, and sometimes you might want to use a different SMS Central. If you notice that receiving SMS messages with your GSM modem works but sending messages does not, you should check the SMSC number and change it manually in the GSM modem gateway properties.
Remove the PIN code
It is strongly advised to remove the PIN code from the SIM card before you use it with the GSM modem. You can enter the PIN code in Diafaan SMS Server and it will use this before logging on to the GSM network. However, if you provide the wrong PIN code to the software or change the SIM card afterwards the SMS software might repeatedly try to enter the wrong PIN code, resulting in a blocked SIM card. When this happens you need to reset the SIM card on a GSM phone using the PUC (Personal Unblocking Code, also known as PUK) you got with the SIM card.
You can use a normal GSM phone to remove the PIN code from the SIM card. Often the default PIN code of the SIM card is 0000, but this is not the same as no PIN code. If you can switch off your mobile phone and switch it on without having to enter your PIN code you can be certain that it is disabled.
See also: Select a GSM modem