Chinese Nokia Lumia 920 has built-in firewall to block calls and SMS

The ability to block unwanted and SMS is a feature that is in high demand by Windows Phone users, which unfortunately is lacking implementation in the today's WP smartphones.
However, now with Windows Phone 8 OEM can use the many new API interface, like the Nokia Lumia 920 Firewall  aka "Nokia Spamfilter" function, will be able to help users solve the harassing phone calls, spam messages and calls attribution to inquiries such distress. 

In China, the theft and sale of private information is a very sensitive issue from population and activity is hidden behind a huge industry which derive profit very well with the activity of spam (junk mail and SMS).

Most likely it is for the reason described in the opening that Nokia has introduced standard function block calls and text messages only in China, because the Chinese population is plagued with this problem more than other countries, so that if a citizen does not receive SMS or email spam is very likely that your account has been closed.

Microsoft, since the birth of Windows Phone 7, has not released APIs that accedessero directly to the phone features of the system , and this did not stop the developers to build of applications that might work by blocking unwanted calls and SMS. now with Windows Phone 8 things look set to change, and at least Nokia can access advanced phone features.

The software pre-installed on the Nokia Lumia 820 and Lumia 920 allows you to:

• Set the block calls on cell phone numbers of our choice
• Block all SMS from a specific sender
• Block dynamically block SMS that contain keywords specified
• Update the online database by keyword
• View all blocked calls and messages
• Tracing the geographical origin of specific phone numbers (only works for mobile numbers)

Now the hope is that soon the other Nokia Lumia will be equipped with this useful and indispensable application. 

Source