WebAPI/WebTelephony/Multi-SIM: Difference between revisions

In the multisim scenario, the phone, the whole device, is using all sim cards that are all on standby. All cards are working separately and they can be connected to different networks simultaneously, like gsm, cdma, etc. Each app should be able to allow user to choose a sim card as the user currently wants. Taking telephony as example, user should be able to choose via which sim card he wants to make a call. User can choose to use a specific sim or simply use the default one. He can call friend A by sim no. 1 and to call friend B by sim no. 2. He is definitely able to receive calls from any sim. Also, among different APIs such as mobile connections and telephony, technically user can set a default sim for 3G data connection and another default sim for telephony voice calls.  

In reality, hardware implementation for multi-SIM scenario varies. Some devices may have one antenna while others have multiple. Some devices may have one modem but others have multiple. If the device has one antenna only, then even in multisim scenario, user is uncapable of placing calls with both sim cards at the same time. If the hardware supports multi-antenna as well, then placing calls with both sim cards at the same time works. Neverthless, in fact, though most existing multisim-devices claim they support multi-sim-standby, they automatically disable other sim card while one is in call. Very few supports the feature fully.