<P> Removable User Identity Module (R - UIM) is a card developed for cdmaOne / CDMA2000 ("CDMA") handsets that extends the GSM SIM card to CDMA phones and networks . To work in CDMA networks, the R - UIM contains an early version of the CSIM application . The card also contains SIM (GSM) application, so it can work on both networks . It is physically compatible with GSM SIMs and can fit into existing GSM phones as it is an extension of the GSM 11.11 standard . </P> <P> This interface brings one of the main advantages of GSM to CDMA network phones . By having a removable identity card, CDMA users can change phones while keeping their phone numbers by simply swapping the cards . This simplifies many situations such as phone upgrades, phone replacements due to damage, or using the same phone on a different provider's CDMA network . </P>

What is the difference between uim card and sim card