AS we known, mobile phone transmit information by wireless , it will produce strong electromagnetic radiation when calling, it will disturb electronic instrument surrounded:
a.in hospital , some medical devices is not allow.
b.blast area, phone may cause explosive.
c.In gas station ,chemicals,flammable gas storage and
transportation warehouse, phone may cause fire.
d.On plane, your phonemay jamming aircraft navigation system.
e.power off during a lightning storm, avoid from lighting attacks.
f.In the high-voltage humid environment Do not call t anybody,prevent from the high voltage electric field damage.
g.when calling in, the surrounded causing big screen jitter or noise, you'd better far away from it.