Conditional call forwarding (CCF) only redirects calls when you can't answer — busy, no answer, or out of coverage. It's the mechanism that powers AI voicemail apps like Katch. Here's exactly how it works on Verizon, AT&T, T-Mobile, and Cricket.
Quick Answer
Conditional call forwarding means calls only forward when you can't answer — not all the time. The three conditions are: No Answer (rings X times then forwards), Busy (you're on a call), and Unreachable (no signal). Most AI voicemail apps including Katch use no-answer + busy forwarding so your phone still rings first.
Conditional call forwarding and unconditional call forwarding sound similar, but they create very different caller experiences. With unconditional forwarding, every incoming call is redirected right away. Your phone usually never rings, which makes it useful only for rare cases like travel, a second business line, or a short test. For most people, it is too aggressive.
Conditional forwarding is the version people usually want. It leaves your normal calling behavior alone until a specific trigger happens. The trigger can be that you did not answer in time, you were already speaking to someone else, or your phone was off or had no coverage. For Katch, use no-answer + busy forwarding. Your phone still rings first, your contacts can still reach you directly, and only genuine missed calls are handed off to Katch. For client intake-heavy practices, it also helps to compare the best voicemail apps for lawyers in the US.
No-answer forwarding lets the phone ring first, then moves the call after a few seconds. It is the most common choice for AI voicemail because you still get the first chance to answer.
Busy forwarding sends callers to the forwarding destination when you are already on a call. Unreachable forwarding is the fallback when your phone is off, in airplane mode, out of battery, or out of coverage.
Verizon is the outlier because one short code often covers both no-answer and busy behavior together. If you are forwarding to Katch on Verizon, *71 is usually the right starting point, not *72. If your line supports a storefront or service team, see how Katch fits small businesses on Verizon.
AT&T gives each condition its own code. Just remember the format: include +1 before the forwarding number and include the closing #. If you run a local company on AT&T, see how Katch fits small businesses on AT&T.
Watch the opening characters carefully
T-Mobile uses ** (double asterisk) — using a single * is the #1 setup mistake and fails silently.
T-Mobile looks similar to AT&T at a glance, but the leading characters are different. If a T-Mobile setup seems to do nothing, double-check the first two symbols before you try anything else.
Cricket runs on AT&T's network. Use identical codes: *61*+1[number]# for no-answer and ##002# to cancel. In practice, if you see an AT&T conditional forwarding guide, it usually applies to Cricket too.
Pick the conditions you actually want
Most people should enable no-answer and busy. Unreachable is optional.
Copy the format for your carrier exactly
Verizon wants a simple 10-digit number. AT&T and Cricket need +1 and a trailing #. T-Mobile needs double asterisks.
Dial from your phone app
Type the code into your dialer and press call. Some carriers confirm silently, so do not rely on audio alone.
Run a real-world test right away
Use a second phone. If forwarding fails, cancel, re-enter the code, and recheck the number format.
Usually it is immediate — within 1-2 seconds of the dial code completing. If not, try toggling airplane mode off/on after dialing because that forces the phone to re-register with the network. AT&T sometimes takes up to 30 seconds to propagate. On T-Mobile, no confirmation tone is not always a problem; that carrier sometimes accepts the code quietly, so the fastest check is to test the behavior right away from another phone.
Wrong country prefix
AT&T, Cricket, and T-Mobile often expect +1 before the 10-digit number. Verizon usually does not. Mixing those formats is one of the most common reasons CCF does not save.
Forgetting the closing #
On GSM-style formats, the final # tells the carrier the command is complete. If you omit it, the dialer may interpret the entry as a partial number instead of a forwarding instruction.
Testing the wrong condition
If you only enabled busy forwarding, simply letting the phone ring will not prove anything. Match your test to the condition you turned on. Busy forwarding needs an active call state, while no-answer needs several rings.
Katch relies on no-answer + busy CCF. This means your phone still rings normally for every call, so you keep your standard call flow and can answer whenever you want. Only calls you genuinely miss because you were busy or did not pick up in time reach Katch's AI. That is the behavior most people expect from an AI voicemail app: help with missed calls, not interception of every call.
Setting unconditional forwarding such as *72 on Verizon would redirect every incoming call without ringing your phone first. That is the wrong behavior for Katch in almost every everyday scenario. If you want a deeper carrier-by-carrier setup guide, see /guides/call-forwarding-us.
Verified against active US carrier dialing patterns used in July 2026. Always test from a second phone after setup because carriers sometimes accept codes quietly.
Conditional forwarding is the setup Katch uses during beta on major US carriers.
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