Change BlackBerry signal strength bar to number mode

The standard signal strength bar on a BlackBerry used to indicate how strong the signal from service provider. The more bars you have, the better the signal strength. But if you prefer more precision, you actually can have the signal strength bar to number mode.

To change your signal strength bar
At home screen, press and hold the ALT key then entering “NMLL” (without quote)
To return to the standard signal strength bar display, enter the same key ALT+NMLL again