A system and method are described for initiating, enabling, disabling or restoring cellphone operations when the cellphone is in a zone, which is where cellphone operation has to be so altered. A courtesy signal transmitter transmits a courtesy signal containing zone data, which is received by the cellphone's courtesy signal receiver. A GPSS receiver, embedded in the cellphone, outputs the current cellphone location. A cellphone's processor compares this location to the zone's coordinates; if it determines that the cellphone is in the zone, the cellphone's processor initiates, enables, or disables operations in it as directed by bits in the zone's data. Spread-spectrum technology securely passes zone data from courtesy signal transmitters to courtesy signal receivers in cellphones, using GPSS data to make this coding scheme more secure. Finally, the courtesy signal transmitter GPSS location is checked to determine if the courtesy signal transmitter has been moved after it is initialized.