SIM security

Can I reactivate my mobile phone account after I have blocked it with my operator?

You should contact your mobile operator to find out if you can reactivate your mobile phone account after you have blocked it, but the answer is likely yes. Keep in mind though, that some operators may require you to pay a fee, visit a store in-person, and/or get a new SIM in order to reactivate your phone.

See also: How can I ensure that nobody accesses my mobile phone?
International

Can I reactivate my mobile phone account after I have blocked it with my operator?

You should contact your mobile operator to find out if you can reactivate your mobile phone account after you have blocked it, but the answer is likely yes. Keep in mind though, that some operators may require you to pay a fee, visit a store in-person, and/or get a new SIM in order to reactivate your phone.

See also: How can I ensure that nobody accesses my mobile phone?
U.S.

I have activated call barring on my SIM card. But I no longer receive MMS and GPRS services are not available. How do I fix this?

Call barring functions should be used with care (they vary from one mobile manufacturer to the next). When blocking calls, either the user explicitly identifies authorized numbers, or they bar a range of numbers, such as international calls. This is the simplest and most widely used of all filters. Frequently the aim is to control call costs when the mobile phone is used by a third party. Subscribers can also use the same approach block data communication such as GPRS.
International

How does a USIM card work?

The USIM (or 3G SIM) is a tiny computer that contains a microchip, complete with memories and interfaces. Compared to a PC or mobile phone, the design has been optimized for protection against attack (equipment and software). There is an operating system, generally based on Java technology, which runs software provided by the operator. One of the core applications manages your subscription. Value added services also give you access to information provided by the operator on voice servers, or by SMS on weather forecasts, financial markets and so on.
International

How does the SIM work?

A small computer and specialized software in the SIM are designed to protect your phone services from unauthorized parties, securely store your personal information like your phone contacts and provide other applications like faster Web searching and ringtone access.  Whether your SIM has these applications or not depends on your service provider, however.  The same wireless phone network that carries your voice conversations also carries information between your service provider and the SIM in your cell phone.  It’s how the network can always find you to give you your phone calls, anywhe
U.S.
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