# Conditional call forwarding explained

> Conditional call forwarding sends a call only when you do not answer, you are busy, or the phone is off. Here is how that differs from forwarding every call.

Published 2026-11-08 · by RingKit · tags: call forwarding, setup, ai receptionist. Canonical: https://www.ringkit.com/blog/conditional-call-forwarding

Conditional call forwarding means your phone rings first. The call goes to another number only in a case you chose: you do not answer, you are already on a call, or the phone is off or out of reach. Forwarding every call is the other setting. That one skips your phone entirely. Most owners who still want to answer the phone themselves want the conditional version, and then they want it to beat voicemail.

This page explains the cases, then the codes two US carriers publish for them, and what to do when your carrier's page does not list a code. The figures below were read from those carriers' own help pages on November 8, 2026. Codes change, and a business phone system often uses a different list than a mobile line. Use the page for your service, not a code from a different company.

## What conditional call forwarding means

Unconditional forwarding (sometimes called immediate or "all calls") sends every incoming call to the other number. Your phone does not ring. That is the right setting on a day off, or when you never want this line to ring in your pocket.

Conditional forwarding is a filter. The usual filters are:

- **No answer.** The phone rings. Nobody picks up. After a set number of seconds, or a set number of rings, the carrier sends the call to the other number.
- **Busy.** You are already using the line, so a second call cannot connect to you. The carrier sends that second call onward. Carriers do not all define "busy" the same way. T-Mobile's short-code page describes busy forwarding as what happens if a call comes in while you are dialing out.
- **Unreachable.** The phone is off, in airplane mode, or outside signal. There is nothing to ring. The carrier can send the call onward instead of failing or going straight to voicemail.

You can turn these on separately. Forwarding only unanswered calls is common. Forwarding all three is what people mean by "send the calls I miss."

The other number has to be a real phone line that answers. RingKit does not port your existing number. You keep it and forward. The overview is the [guide to forwarding a business number](https://www.ringkit.com/blog/forward-business-number-to-ai-receptionist).

## Why voicemail answers first

Conditional forwarding and voicemail are both waiting for the same event: you did not pick up. Whichever timer is shorter wins.

If voicemail starts first, callers leave a recording and the receptionist never hears them. The forward can look successful in your settings and still do nothing. Test before you tell customers the line is covered.

[Verizon's wireless page for turning forwarding on](https://www.verizon.com/support/knowledge-base-181139/) states the intended outcome for its conditional code in one sentence: if the phone is busy or unanswered after 3 to 6 rings, the call goes to the number you chose instead of voicemail. [AT&T's wireless page](https://www.att.com/support/article/wireless/KM1011513/) says call forwarding overrides wireless voicemail, and that if the number you forward to is busy, the caller hears a busy signal. Those are different behaviors. Read the page for the carrier you actually pay.

If a test call reaches voicemail, shorten the ring delay for the forward, or turn off voicemail for that line, and test again from a phone that is not the one you just programmed. The [test checklist](https://www.ringkit.com/blog/test-call-forwarding) is the sequence to run.

## Verizon wireless codes

These codes are not universal. A T-Mobile code on Verizon, or a mobile code on a desk phone, does something else or nothing.

[Verizon's on page](https://www.verizon.com/support/knowledge-base-181139/) says:

- `*72` and then the 10-digit number forwards all calls. The phone will not ring.
- `*71` and then the 10-digit number is conditional: busy or unanswered after 3 to 6 rings, instead of voicemail.

[Verizon's off page](https://www.verizon.com/support/knowledge-base-17268/) says `*73` turns off immediate or conditional forwarding. Listen for beeps and wait for the call to end. [Their FAQ](https://www.verizon.com/support/call-forwarding-faqs/) says the confirmation can sound like a busy signal. That tone is not, by itself, proof that forwarding failed.

The destination has to be a working US voice number, 10 digits, not international. Texts are not forwarded. Dial the code from the wireless phone while you are on Verizon's network. A star code may not work outside that coverage. Do not reuse these codes on another carrier.

## T-Mobile short codes

[T-Mobile's short-code page](https://www.t-mobile.com/support/plans-features/self-service-short-codes) says the codes are country specific, that most of them go to the primary SIM, and that some plans do not support short codes that are not T-Mobile's. The forwarding codes on that page are:

| Case | Turn on | Turn off |
|---|---|---|
| All calls | `**21*` then `1` and the 10-digit number, then `#` | `##21#` |
| No reply | `**61*` then `1` and the number, then `#` | `##61#` |
| Not reachable (off or no signal) | `**62*` then `1` and the number, then `#` | `##62#` |
| Busy | `**67*` then `1` and the number, then `#` | `##67#` |

`##004#` resets call forwarding to the default. For no-reply, the same page shows a delay: after the number, add `**`, the seconds, and `#`. The delays it lists are 5, 10, 15, and up to 30 seconds. Their example uses 10 seconds. Use your destination number, not the sample number printed on T-Mobile's page.

T-Mobile describes the busy code as the case where a call arrives while you are dialing out. Do not assume it also covers every "I am already talking" situation until you have tested that on your own line.

## When the carrier does not list a code

AT&T's wireless call-forwarding article, last updated April 2, 2025, does not print star codes. It says you can change forwarding only from the wireless phone, not online. It also says forwarding overrides wireless voicemail, you cannot forward to an international number, and a busy destination means the caller hears a busy signal. Forwarded calls are billed for their length, and long-distance or roaming charges can apply.

If your page looks like that, use the carrier's device tutorial for your phone instead of borrowing `*72` from Verizon. A code that is right on one network is a wrong number on another.

A desk phone or hosted system uses its own codes or an admin site. If the call hits that system first, the mobile codes never run.

## iPhone settings are not the conditional feature

On an iPhone with GSM service, [Apple's guide](https://support.apple.com/guide/iphone/set-up-call-forwarding-iph7405291c4/ios) puts call forwarding in Settings, then Apps, then Phone. You turn on Call Forwarding and enter one number. Apple says that if the carrier supports conditional forwarding when the line is busy or not in service, you contact the carrier for that setup. The Settings switch is not where you choose "after four rings."

If the menu is missing, Apple says CDMA service needs the carrier's instructions. That is a reason to open the carrier's page, not a reason to keep tapping. A separate iPhone article on this blog follows Apple's steps and stops where Apple stops.

## How to know it worked

Call your business number from a different phone. For all-calls, your phone should not ring. For conditional, it should ring, and the other number should answer only after you let it. Then try once while you are already on a call, and once with the phone off. Who answered is the test. "The setting says on" is not.

Call the destination before you forward, and ask a question the brief should answer. The test checklist on this blog is the same sequence written as steps. Verizon and AT&T both say carrier forwarding can be billable on the mobile plan. RingKit's own number charge and per-minute rate are on the [pricing page](https://www.ringkit.com/pricing), and this article does not repeat them.

Developers setting up the receptionist, rather than the carrier forward, use the [docs](https://www.ringkit.com/docs). An API cannot dial `*71` for you.

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