An ESN is the Electronic Serial Number assigned to your iPhone and is used with CDMA phones. The ESN has been tied directly to the phones with CDMA carriers such as Verizon Wireless and Sprint. With the introduction of 4G service, a sim card has now been introduced, however, there remains an ESN tied directly to the phone itself in addition to a number on the sim card.
- ESN is an Electronic Serial Number that is unique to each CDMA phone.
- The ESN number cannot be legally, nor easily changed.
- A phone's ESN is like a fingerprint.
Verizon phones are identified by the ESN number when connecting to the service network. The ESN is matched to a massive inclusive database. If the ESN number does not exist in the database, or is marked as bad, the mobile phone will not be allowed to activate with any account, without regards to the status of the account.
- An ESN is either CLEAR or BAD
- Only a clear ESN can be activated on Verizon.