OnePlus
Enable or Disable Call Waiting auf OnePlus
Call waiting on OnePlus phones controls what happens when a second call arrives while you are already talking to someone. With the function enabled, you hear a short tone and can choose to reject the new call, put your current call on hold, or switch between both. With it disabled, any second caller hears a busy signal or gets sent directly to voicemail, and you never see an on-screen notification about the incoming call.
This setting lives inside the calling accounts of the Phone app, not in the general system settings. On dual SIM devices, each SIM card has its own independent call waiting toggle, so enabling it for one line does not affect the other.
To change it, open Open the Phone app ➔ Open the menu ➔ Open the Settings ➔ Tap on Calling accounts ➔ Choose a SIM card (Dual SIM) ➔ Tap on Additional settings ➔ Enable or disable Call waiting.
Turn it off if you want zero interruptions during calls, for example while recording audio or in meetings. Turn it on if you rely on catching urgent second calls, such as for work or family emergencies. Note that call waiting depends on carrier network support in some regions, so if the toggle has no effect, check with your carrier first.