How do I collect keypad input during a phone call?

To collect keypad input during a phone call, you typically use DTMF tones — the tones generated when someone presses keys on a phone.

Common approach

1. Play a prompt
   Example: “Press 1 for sales, 2 for support.”

2. Listen for DTMF digits Your telephony platform should expose an event or API for keypad input.

3. Handle the digit(s) Route the call based on what the caller pressed.

If you’re using a voice API / telephony platform

Most platforms provide something like:

• Gather / GetDigits
• collect digits
• input="dtmf"
• DTMF event callbacks/webhooks

Example flow

• Answer call
• Say “Press 1 for billing, 2 for tech support”
• Wait up to, say, 5 seconds for input
• If digit received, branch accordingly
• If no input, repeat or route to operator

Example in pseudocode

play("Press 1 for sales, 2 for support")
digit = wait_for_dtmf(timeout=5)

if digit == "1":
    transfer_to_sales()
elif digit == "2":
    transfer_to_support()
else:
    play("Sorry, I didn't catch that.")

If you’re building with SIP / low-level telephony

You may receive DTMF in one of these ways:

• RFC 2833 / RFC 4733 (out-of-band RTP events)
• SIP INFO
• In-band audio tones (less reliable)

The best method is usually RFC 4733.

Important tips

• Set a timeout and max number of digits.
• Confirm whether your system collects:
  • single digit
  • fixed-length PIN
  • “#” terminated input
• Make sure the call leg is in a state that can receive DTMF.
• If you also want spoken input, many systems let you combine speech + DTMF.

If you tell me what platform you’re using (Twilio, Asterisk, FreeSWITCH, SIP.js, Genesys, etc.), I can show the exact way to do it.