Re: cell phone CDMA
If you want to use dual mode digital service, it has to be CDMA--not TDMA or GSM--and not coded to a particular company from outside the Dominican Republic. For example, it can't say Sprint, AT&T, or Cellular One on the phone. That would indicate that they own the coding and Codetel or Tricom don't have access to their programming.
An analog only phone will work when activated locally in the Dominican Republic. I have also heard that some phones can be activated on the analog side only of dual service, but have no personal experience. Roaming is also possible with some off-island agreements.