Some devices have an IMEI number instead of a DEC or HEX. Don't worry if your phone doesn't show this but if it only has an IMEI, we can convert it for you!
This will be an (18) digit number that can be found on a sticker under your battery or in phone settings.
(Very Common for 3G CDMA Devices). This will be a (14) character value that can be found on a sticker under your battery or in phone settings.
What brand is the phone you're trying to activate?
Every phone has a model number. Sometimes, this can be found on the sticker under your (removable) battery and other devices require you to look in phone settings.