 A different problem occurs when ESN codes are stored in a database (such as for OTASP).In this situation, the risk of at least two phones having the same pseudo-ESN can be calculated using the birthday paradox and works out to about a 50 per cent probability in a database with 4,800 pseudo-ESN entries.3GPP2 specifications C.S0016 (Revision C or higher) and C.S0066 have been modified to allow the replacement MEID identifier to be transmitted, resolving this problem.