Dual SIM capability is not handled by SIM provider it is handled by the Processor used in mobile. So there is no any relation between two GSM provider you are using. If your processor is smart enough to sense that there is incoming call on other SIM then they can give you acknowledge on same. In this case both GSM modem running in parallel (Samsung phone is example of such).gwendollenIn our dual sim mobiles,suppose we are in call via 1st sim..if another person calls to the 2nd sim why cant that person hear the ring or atleast call waiting??i know we cant hear ring practically....but theoritically the two sim's are independent to each other and also each sim and phone are not connected physically...sim is just an interface....then what is it the reason that the service providers cant able to provide this compatibility to the mobiles???
This gives information on all the dual sim varieties https://en.wikipedia.org/wiki/Dual_SIM
Is there any way that if i am using sim 1 and i am on call and any other person calls me either on sim 1 or sim2 then both the numbers say not rechable or switched off so that other person dont come to know that phone was busy
It happens with Xiaomi dual SIM phones. But the other person does get a busy tone. I myself have experienced this several times.
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