4 Code for iPhone

Signal Check
Input the following in the dial pad
*3001#12345#*
Then press "dial"
>-50dBm  indicates signal strength is very good

-50 to -70 indicates signal strength is pretty good

-70 to -90 indicates signal strength is normal

'-90' - '-100dBm' indicates signal strength is normal


Incoming Call status (turn on call forward or not)
Input the following in the dial pad
*#21#
Then press "dial"

IMEI Number

Input the following in the dial pad
*#06#
Then press "dial"


Show the Support Number of Service Provider

Input the following in the dial pad
*#5005*7672#

Then press "dial"

Five usages of "Delete" key in Mac

In Mac, when "delete" key is pressed, Mac deletes a character of the left hand side of the cursor.

And any other usages ?

1. Press "fn" and "delete" key at the same time, Mac deletes a character of the right hand side of the cursor.

2. Press "option" and "delete" key, Mac deletes a whole word of the left hand side of the cursor.

3. Press "command" and "delete" key, Mac deletes the whole line.

4. Select a file or files and press "command" and "delete", Mac deletes the selected file(s) to recycle bin.