I have an optimized sim card can I buy a GSM phone and use the CDMA card for it to work on that network?
In order to work with a CDMA network, the phone in question must have the needed hardware to do so. Some phones are truly GSM only. Please see here for more: Republic Wireless Phones – Republic Help.
Additionally, may we know where this optimized CDMA SIM originated from? Was it ever activated in another Republic phone?