When I block certain number, what happens when that person tries to send me sms or call me? What does that other person see? Do they know I blocked them or how is this handled? Thank you
The blocked person here will see a "Line Busy" status while he calls you. For SMS, he will also get delivered messages like normal cases. These will be no indication that you have blocked him what so ever. On your side, if you go to settings >> call+SMS filter, you can find the blocked calls ans SMS.
Actually here the phone OS receives both the blocked calls and SMS, but lets you have peace by not notifying you for the blocked numbers, that's all.