Hold, Mute & DTMF

Place callers on hold, mute your microphone, and send touch-tone digits during calls.

During active calls, you can hold, mute, and send DTMF tones using the in-call control bar or keyboard shortcuts.

Mute

Mute silences your microphone. The caller cannot hear you, but you can still hear them.

Action	How
Toggle mute	Click the Mute button, or press M

When muted, the microphone icon shows a strikethrough and a “Muted” label appears.

When to use: speaking with someone else in the room, taking notes, handling background noise.

Hold

Hold places the caller on hold with hold music. Both sides know the call is paused.

Action	How
Toggle hold	Click the Hold button, or press H

The hold request is sent to the server via POST /v1/calls/{callSid}/hold. The contact header shows a yellow status dot and “On Hold” label while hold is active.

When to use: looking up information, consulting with a colleague, preparing for a warm transfer.

During a warm transfer, the caller is automatically placed on hold. You don’t need to hold them manually — the transfer flow handles it.

DTMF tones

DTMF (Dual-Tone Multi-Frequency) lets you send touch-tone digits during a call. This is how you navigate automated phone systems, enter PINs, or dial extensions.

Action	How
Open DTMF keypad	Click the Keypad button in call controls
Send a digit	Click the digit on the keypad, or type it on your keyboard
Close keypad	Press Escape or click outside the keypad

Supported keys: 0-9, *, #. Long-press 0 to send +.

Common uses:

• Entering conference call PINs
• Navigating IVR menus (“press 1 for sales”)
• Dialing extensions
• Accessing voicemail systems

Visual indicators

The contact header and call controls update in real time to reflect the current state:

State	Status dot	Label	Controls
Connecting	Blue, pulsing	”Connecting…”	End call only
Ringing	Blue, pulsing	”Ringing…”	End call only
Active	Green	Call timer	Full controls (mute, hold, transfer, keypad, end)
Muted	Green	”Muted”	Mic icon crossed out
On hold	Yellow	”On Hold”	Hold button highlighted
Ended	Gray	”Call ended”	Post-call summary appears
Failed	Red	Error message	Retry or dismiss

Error handling

If the hold request fails (e.g. the call ended on the server side), an error bar appears at the top of the call controls with the error message and a dismiss button.

If the Twilio device encounters an error mid-call, the controls show a reconnection banner with Reconnect and End Call options.

Keyboard shortcuts

Shortcut	Action
M	Toggle mute on/off
H	Toggle hold on/off
T	Open transfer dialog
Escape	Close keypad or cancel current action

These shortcuts only fire when you’re not focused on a text input field.

Next steps

• Transfers — hand off calls to colleagues
• Keyboard Shortcuts — full shortcut reference