Removable User Identity Module
From Wikipedia, the free encyclopedia
Removable User Identity Module (R-UIM) or a CSIM [CDMA Subscriber Identity Module] is a card developed for CDMA handsets that is equivalent to the GSM SIM and 3G USIM except that it is capable of working in both CDMA and GSM phones and 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 [1].
The card 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.
A CSIM is defined as a CDMA2000 application on UICC, an evolution to the R-UIM. It is defined in standard [2]
This form of card is widely used in China under the CDMA service of China Unicom. However, it is also used elsewhere such as India, Thailand, and Japan.
