All dual SIM handsets have dedicated SIM card settings in the Settings menu to customise as per your requirement. Going to these settings, you can select which SIM is used for telephony and which for Internet. However, bear in mind that if you use 4G LTE network, in some smartphones only the primary slot supports the same.

Dual SIM Active smartphones are complete opposite of dual standby. Handsets with this feature have both SIM cards active at the same time always, which means even if you are on call using one SIM, the other will remain active and receive calls as normal. This is more preferred by many as you do not miss out on important calls. The Dual Standby mobiles use a single transceiver that caters to only one SIM at a time. While, on the other hand, dual Active mobiles comes with dual transceivers that can handle each SIM at any given time.

Today every smartphone, except for few high end ones, come with the dual SIM feature, however, there is a catch. If you are looking for a dual SIM handset for daily use, make sure that it is not a dual standby handset. What this term means is that when you are not using the handset, both SIM cards are active at the same time. However, as soon as you receive a call on one SIM, the other will become dormant and people calling on it will get the message that the number is not reachable. This might not be an ideal scenario for those who want both numbers to be active.

With a Hybrid SIM card slot you can either use dual SIM cards or a single SIM card along with a microSD card. Therefore, if you are someone who uses both dual SIM card and memory card expansion, this is not for you as a phone with dual sim and an expandable storage separately would be ideal for you. However, it comes handy if you decide to use only a single sim or expand the storage of your device at a later stage any time.