(ME)ID Required
MEID is a 56-bit serial code meant to replace ESNs for identifying phones on networks as well as securing calls and other ESN functions. By using a 56-bit code, MEID will have a much longer lifespan. The TIA will also maximize MEID's lifespan with stingier rules about assigning blocks of codes. As an added bonus, since it is the same length as IMEI, it will be possible to assign a single code to a multi-radio device.
MEID was originally intended to be implemented when carriers upgraded their networks to CDMA 2000 EV-DV, Revision D. At that time there were supposed to be enough remaining ESNs to assign to TDMA phones on the few remaining networks while all future CDMA handsets would receive MEIDs since the upgraded networks would use MEIDs to identify the phones.
Recently, EV-DO Revision A has replaced EV-DV on carrier roadmaps. Since MEID compatibility was slated for EV-DV rollouts, the industry was caught in a lurch. ESNs were running out and no one had an MEID-compatible network on their roadmap. The industry needed to come up with a stop gap solution, or two.