Brother, when you enter the password on your mobile, an option appears called PIN. If you go into that option, you will also see SIM lock and your SIM code shown as one two three four. By pressing those (or entering those) you can stop it — like that your mobile gets locked — or you can unblock your SIM using the PUK code. There is also an option that if you enter the wrong code three times, it becomes permanently blocked. If you enter the wrong PUK three times, you will first have to enter the PUK code, and to find the PUK you can also use the IDR (or seek help from customer care) to get information about it. If you enter the PUK incorrectly three times, you will have to buy a new SIM from a store — the same SIM won’t work again; it becomes permanently blocked. It becomes completely useless — it won’t work in any phone, neither a new phone nor an old phone. If the SIM has become useless, that’s it. To save it, I’m telling you this: if you want to set a password, go to Security and set a password for your mobile. Do not click the PIN option. There are many options below like Privacy, Phone Lock, or Other Things — you can click those. But clicking the PIN makes the SIM insecure. If you put a password there, remember that PIN does not refer to the phone password — it’s called PIN for the SIM. When you click PIN, the options shown below are Phone Lock, Privacy, Quality (?) and other things where you can set passwords for things like Camera, Settings, File Manager and other apps. But the PIN option is only for the SIM system — you cannot put your phone password there. It is given specially for the SIM. On any phone, whether a keypad phone or an Android phone, putting the SIM PIN is very dangerous.
