Abstract: In accordance with the invention there is provided a time control system for a cellular telephone having a control circuit, which includes an external control having a timing input arrangement for receiving use-time available to a user of the cellular telephone, an interface box connected with the external control detachably connected with the cellular telephone, an interface transmission module in the interface box, an internal data transmission circuit in the cellular telephone, a disconnectable transmission arrangement disposed between the interface transmission module and the internal transmission circuit, an internal timing control circuit in the cellular telephone having a timing storage arrangement for storing use-time available to the user of the cellular telephone, the cellular telephone control circuit having a disabling input connected with the internal timing control arrangement for disabling the cellular telephone upon expiration of use-time stored in the timing storage arrangement.