Calling a mobile phone number repeatedly and not getting an answer can be frustrating. When this happens, you might wonder whether the person you are calling is receiving your call and not bothering to answer or has simply turned off the cellphone. It’s possible for you to determine whether a mobile phone is communicating with the wireless network when you call. The number of rings indicates whether the phone is receiving a signal.
Dial the mobile phone number.
Press the "Send" or "Flash" button if you are calling from another mobile phone or a cordless phone
Count the number of rings. If your call goes straight to voice mail without ringing, the phone is turned off or it is not receiving a signal. If the phone rings before your call goes to voice mail, the phone is on.