Sec. 22.919  Electronic serial numbers.

    The Electronic Serial Number (ESN) is a 32 bit binary number that 
uniquely identifies a cellular mobile transmitter to any cellular 
system.
    (a) Each mobile transmitter in service must have a unique ESN.
    (b) The ESN host component must be permanently attached to a main 
circuit board of the mobile transmitter and the integrity of the unit's 
operating software must not be alterable. The ESN must be isolated from 
fraudulent contact and tampering. If the ESN host component does not 
contain other information, that component must not be removable, and its 
electrical connections must not be accessible. If the ESN host component 
contains other information, the ESN must be encoded using one or more of 
the following techniques:
    (1) Multiplication or division by a polynomial;
    (2) Cyclic coding;
    (3) The spreading of ESN bits over various non-sequential memory 
locations.
    (c) The ESN must be factory set and must not be alterable, 
transferable, removable or otherwise able to be manipulated. Cellular 
mobile equipment must be designed such that any attempt to remove, 
tamper with, or change the ESN chip, its logic system, or firmware 
originally programmed by the manufacturer will render the mobile 
transmitter inoperative.