Neither iPhone nor Android has a setting called “give callers a busy signal.” What most people want is for a call to stop ringing and for the caller to get a busy tone or go straight to voicemail, as if you were on another call. Depending on your phone and carrier, you can get close to that with a few built-in tools: declining the call, Do Not Disturb or Focus modes, silencing unknown callers, blocking a number, or carrier call-forwarding settings. This guide explains what each one does from the caller’s side, so you can pick the right one.
Quick answer
To end a call quickly, press the side or power button twice (iPhone) or tap Decline. The caller usually goes to voicemail. To stop all calls for a while, turn on Do Not Disturb. What the caller hears depends on your carrier, and a true busy signal usually requires a carrier call-forwarding setting.
Option 1: Decline the call
- iPhone: Press the side button twice, or tap Decline if the call shows full screen.
- Android: Swipe or tap Decline. Many Android phones also let you send a quick text such as “Can’t talk now, call you later.”
What the caller hears: Usually the call goes to voicemail after a ring or two. On some networks, it can sound like a busy line.
Option 2: Do Not Disturb or Focus
- iPhone: Open Control Center and tap Focus > Do Not Disturb. You can allow calls from favorites or let repeated calls through. See finding Do Not Disturb on iPhone.
- Android: Swipe down from the top of the screen and tap Do Not Disturb. Set exceptions in Settings > Sound (or Notifications) > Do Not Disturb.
What the caller hears: The phone doesn’t ring for you, and the caller typically reaches voicemail.
Option 3: Silence unknown callers
On iPhone, go to Settings > Apps > Phone (or Settings > Phone on older iOS) and turn on Silence Unknown Callers. Calls from numbers not in your contacts go silently to voicemail. Many Android phones have a similar filter in the Phone app’s settings. See silencing unknown callers on an iPhone.
Option 4: Block a specific number
If one person or spammer keeps calling, block them. On iPhone, open the Phone app, tap the i next to the number in Recents, and tap Block this Caller. On Android, open the Phone app, tap the number, and choose Block.
What the caller hears: On iPhone, blocked calls go straight to voicemail. On Android, it depends on the phone and carrier.
Option 5: Carrier call forwarding for a busy signal
Some carriers let you set what happens to unanswered or declined calls, through the phone’s Call forwarding settings or short codes from the carrier. Options and codes vary a lot between carriers and countries, and some settings can’t be changed by the customer at all. Check your carrier’s help pages or support line before changing forwarding, because a wrong setting can send all your calls somewhere unexpected.
Option 6: Airplane mode
Turning on airplane mode disconnects your phone from the network. Callers usually go straight to voicemail. You won’t get texts or data either, unless you turn Wi-Fi back on.
Which option should you use?
- One call right now: Decline it.
- A meeting or bedtime: Do Not Disturb or a Focus.
- Spam calls: Silence unknown callers.
- One persistent caller: Block the number.
Frequently asked questions
Can the caller tell I declined their call?
Sometimes. If it goes to voicemail after one ring instead of the usual four or five, some people notice. Do Not Disturb usually lets it ring normally on their end before voicemail picks up.
Will apps that claim to fake a busy signal work?
Results vary, and many rely on the same carrier forwarding tricks or need broad access to your calls. Built-in options are safer.
Does this work for WhatsApp or FaceTime calls?
Do Not Disturb and Focus modes silence those too, but the caller sees that you didn’t answer rather than a busy line.
Summary
- Phones don’t have a built-in busy-signal setting.
- Decline, Do Not Disturb, and blocking send callers to voicemail.
- Silence unknown callers to cut spam.
- Ask your carrier about call-forwarding options for a busy tone.
Kermit Matthews is a freelance writer based in Philadelphia, Pennsylvania with more than a decade of experience writing technology guides. He has a Bachelor’s and Master’s degree in Computer Science and has spent much of his professional career in IT management.
He specializes in writing content about iPhones, Android devices, Microsoft Office, and many other popular applications and devices.