Page "Advanced Mobile Phone System" Paragraph 4

It suffered from some weaknesses when compared to today's digital technologies.

Since it was an analog standard, it is very susceptible to static and noise and has no protection from eavesdropping using a scanner.

In the 1990s, " cloning " was an epidemic that cost the industry millions of dollars.

An eavesdropper with specialized equipment could intercept a handset's ESN ( Electronic Serial Number ) and MIN ( Mobile Identification Number, aka the telephone number ).

An Electronic Serial Number is a packet of data which is sent by the handset to the cellular system for billing purposes, effectively identifying that phone on the network.

The system then allows or disallows calls and or features based on its customer file.

If an ESN / MIN Pair is intercepted, it could then be cloned onto a different phone and used in other areas for making calls without paying.