Free Call Trick

Actually this is just a simple trick but only few person realise about it..

just make a call but only about 0-2 seconds..

this trick can be used for a short message, like when you already home

you can call anyone in the house by just said "open the door now" and its free..

but this trick is not efficient to be used for important and urgent long talk.

Notes: This trick only work for few SIM Operator..so you may try whether your operator support it or not