PART VII. THE ELECTRONIC SERIAL NUMBER - AN INTRODUCTION When a cellular phone is removed from factory packaging, the ESN normally can be found in the document package (or on a sticker stuck to the phone). This ESN is usually correct and system registration procedes quickly. If the phone is used or has been turned off for non-payment of bills, the person who restores the service needs the ESN in order to program the system with an MIN. Every manufacturer assigns their own ESN, consequently it is possible to have a number of the same ESN's, although each may be produced by a seperate manufacturer. For example, there may be a Motorola ESN of 123456, an Audiovox ESN of 123456, etc. With this in mind it is a possibility that a person could broadcast without changing the ESN, but rather changing the SCM and the SIDH. The ESN is a 32-bit number which uniquely identifies each unit. This ESN is factory programmed and installed and cannot be changed in the field without removing it and reprogramming a new chip. The ESN may or may not be related to the serial number stamped on the outside of the transceiver chassis. The ESN is encoded into messages which are interchanged with the cellular tower. The ESN must be provided when the phone is registered for service. The ESN is an 11-digit number. THE FIRST THREE NUMBERS ARE THE MANUFACTURERS DECIMAL CODE, THE NEXT TWO ARE RESERVED (BUT MAY CONTAIN ZEROS OR NUMBERS) AND THE REMAINING SIX ARE THE DECIMAL SERIAL NUMBER. *****************************************************************************