Calling a mobile phone from a device

[sripathys]

I have an idea of developing a low cost economical device which should have the capability of alerting a user mobile phone through SMS and calling the mobile phone of a user to play an announcement.

The mobile phone user can be within an operators network coverage.

I have seen the merits and de-merits of various devices ( RFId , IrDa and Bluetooth ) to be used in Near Field communications unable to decide on a suitable device .

Can some one suggest a suitable device .

[honest_success]

I have an idea of developing a low cost economical device which should have the capability of alerting a user mobile phone through SMS and calling the mobile phone of a user to play an announcement.

The mobile phone user can be within an operators network coverage.

I have seen the merits and de-merits of various devices ( RFId , IrDa and Bluetooth ) to be used in Near Field communications unable to decide on a suitable device .

Can some one suggest a suitable device .

As you have read the merits and demerits of all the things so i think you should be able to decide. If you are looking for security then you have to compromise with distance(NFC). If you want distance then you have to some what compromise with security(bluetooth) etc.