Change the no-reply timer: ring time before forwarding, by carrier

Step 1: See what it's set to now

On many carriers that use GSM-type codes, open the Phone app's keypad, dial *#61#, and press call. If your carrier supports it, you'll see a message showing where unanswered calls go, and often how many seconds it waits. Write down that phone number exactly. It's usually your voicemail number.

If you get an error, your carrier doesn't support the code. Skip to "When there's no code."

Step 2: Dial the code with a longer wait

T-Mobile publishes this code on its own support page:

**61*[the number from step 1]**[seconds]#

The seconds can be 5, 10, 15, 20, 25, or 30. T-Mobile's page gives its own voicemail number as the example. Dialing this would set a 30-second wait:

**61*18056377243**30#

Use the number your phone showed you in step 1, not someone else's. If you forward unanswered calls to a colleague or an office line, use that number instead. Then dial *#61# again to confirm the new setting.

When there's no code

• Verizon. Verizon's help page says its no-answer forwarding (*71 plus the number) sends calls on after three to six rings. It doesn't publish a code to change that. Ask Verizon support whether they can adjust it on your line.
• AT&T. AT&T's voicemail help lists changing the number of rings before voicemail as something you can manage, but we couldn't confirm a self-serve code on AT&T's own pages. Call AT&T and ask, or try the code above and see whether your phone says it worked.
• Smaller and prepaid carriers. Some run on a bigger carrier's network and accept the same code. Some don't. Their customer service will know.
• Office and internet phone systems. Desk phones and business phone apps usually have a ring-time setting in the admin area. Ask whoever set up the system.

On iPhone: check Live Voicemail first

If Live Voicemail is on, your iPhone can pick up an unanswered call itself, so a longer carrier timer may seem to change nothing. Go to Settings → Apps → Phone → Live Voicemail, turn it off, and test again. If calls still skip your forwarding, here's why an iPhone sends calls to voicemail instead of forwarding.

How long is long enough?

Longer isn't always better. If it rings too long, some callers hang up before voicemail or the forwarded phone ever answers. Pick the time that gives you a real chance to get to the phone, then stop. Also, what the caller hears and what your phone plays aren't always the same length.

Test it

Ask someone to call you and let it ring out. Count how long it takes before the call moves on, and check that it lands where you want. Do this after every change.

Under the hood

The codes are GSM supplementary-service (MMI) strings the handset sends to the network:

• *#61# interrogates call forwarding on no reply and usually returns the forward-to number and the timer.
• **61*number**seconds# registers no-reply forwarding to that number with that timer. The standard range is 5 to 30 seconds in 5-second steps. T-Mobile publishes this exact form.
• ##61# erases no-reply forwarding. On T-Mobile, ##004# resets all forwarding to the default.

Carriers that don't expose these strings handle the timer in their own provisioning systems, so only support can change it. On iPhone, on-device Live Voicemail can take the call before the network timer expires, which hides any change you make. Disable it while testing.

Short close

Dial *#61# to see the current setting. If your carrier accepts the code, set a longer wait with **61*number**seconds#. If it doesn't, call them. On iPhone, turn off Live Voicemail, then test with a real call.