ESN
Electronic Serial Number
A unique identifier assigned to a mobile device.
An ESN is a unique identifier historically assigned to cellular devices to register them on a carrier network and deter cloning or fraudulent use. It functions as a hardware level serial number that links a handset to subscriber records. Older ESNs were largely succeeded by the longer MEID and by the IMEI used on GSM networks, which serve the same device identification role. The exam relevance is recognizing it as a device identifier within mobile asset tracking and provisioning rather than a security control by itself.
Looking ESN up is step one. Getting tested on it is step two.
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