Samsung
Allow Both SIM Cards to Use Mobile Data During Calls auf Samsung
On Samsung dual-SIM phones, the data connection normally stays tied to whichever SIM you use for browsing and messaging. During a call, the second SIM's radio pauses to save battery and avoid network conflicts, which is why data traffic can stall until the call ends.
The Allow all SIMs to use data in calls toggle in the network settings tells the system to keep both SIMs active for data even while one of them is handling the call. This helps when you rely on background downloads, live location sharing, or chat apps that need a constant connection during a phone call.
To turn it on, open Settings ➔ Connections ➔ Mobile networks and switch on Allow all SIMs to use data in calls. Switch it off again once you notice faster battery drain, since keeping both radios awake at once uses more power.
This setting only affects Samsung devices with two active SIM slots. On a single-SIM setup, or when one slot holds an eSIM without its own data plan, the toggle has no effect.