Human Add AI help center covers call forwarding setup for every major US carrier (Verizon, AT and T, T-Mobile, Spectrum, Comcast, RingCentral, Google Voice, OpenPhone, and twelve more), PWA install instructions for the mobile dashboard, knowledge base editing, and account management. Most setup guides take under five minutes to complete.
AT&T uses a GSM-style star code to control call forwarding. This guide covers both the star-code method and the myAT&T app, with the exact dialing format.
The quick version
On your AT&T phone, open the dialer and enter **21* followed by the 10-digit number you want calls forwarded to, then press call. To turn forwarding off, dial ##21#.
Step-by-step: enable call forwarding on AT&T
1
Open the phone dialer app on the AT&T line you want to forward. You'll enter a short code the same way you'd enter a phone number.
2
Type**21* followed immediately by the 10-digit number you want calls forwarded to. No spaces, no dashes, no "+1". Example: **21*5551234567.
3
Press the call/send button. You'll hear a short confirmation tone or a brief recorded message, then the call ends automatically.
4
Test it. From a different phone (or ask a friend), call your AT&T number. It should ring at your forwarding destination, not your cell.
To turn forwarding off
Open the dialer, enter ##21#, and press call. You'll hear a confirmation. Your line is back to normal immediately.
Conditional forwarding (only when you don't answer)
Sometimes you want to handle some calls yourself and forward the rest. "Conditional" call forwarding routes calls only when your line is busy, unanswered, or unreachable. For conditional forwarding (only when busy or not answering), dial **61*NUMBER# to enable and ##61# to disable. AT&T also supports **62* for "when unreachable" and **67* for "when busy."
Using the AT&T app instead
You can also manage call forwarding from the myAT&T app: tap Account → your wireless line → Manage my device features → Call Forwarding. Toggle on, enter the destination number, save. This is the easiest path if you prefer a UI to star codes.
Things worth knowing
AT&T's codes use a specific syntax: **21* then the 10-digit number then #, with no spaces. Full example to forward to 555-123-4567: **21*5551234567# then press call.
Some older AT&T feature phones used *72 / *73 instead. If **21* doesn't work, try those - they'll work on legacy accounts.
Call forwarding is included on all AT&T postpaid wireless plans. Cricket Wireless (owned by AT&T) also supports the same **21* syntax.
Forwarded calls don't consume minutes on AT&T Unlimited plans.
Forwarding to an AI receptionist?
The whole reason you're reading this is probably to stop missing calls. If you're setting up call forwarding to send calls to a voice assistant, an answering service, or an AI, the steps above are the same - you just enter their number as the forward-to destination. Human Add AI gives you a dedicated AI receptionist that answers 24/7, captures every caller's intent, and texts you the details. Try it free for 7 days →
Troubleshooting
You hear an error or fast busy signal. Double-check you entered a valid 10-digit number with no extra characters. Some AT&T plans (pre-paid especially) don't include call forwarding - if it still won't set up, call AT&T and ask them to enable "call forwarding" on your line.
Calls still ring your cell. Forwarding can take up to a minute to activate. Wait 60 seconds and test again. If it's still not working, dial ##21# to clear it, then redo the enable code.
You want to stop forwarding but don't remember the code. Dial ##21# from the forwarded line. That's the universal "cancel all forwarding" code on most networks.
Voicemail is picking up before the forward kicks in. That's usually because your voicemail delay is set shorter than the forward. If you want forwarded calls to always get through, use unconditional forwarding (**21*) instead of conditional.
Every Human Add AI trial gives you a dedicated local phone number with a fully custom AI receptionist on the other end. Free for 7 days, $10 refundable activation.
Starter is $497 a month for up to 200 calls, with one AI assistant and one business number. Professional is $997 a month for unlimited calls and up to 3 AI assistants, and connects to your CRM (the software you track customers in). Enterprise starts at $1,997 a month. Every plan answers 24/7, books appointments and texts you each lead. Start with a 7-day free trial ($10 activation fee, credited to your first bill), backed by a 30-day money-back guarantee. See full pricing or call the demo line at (617) 812-5251.
What changes after the first month on the platform
After thirty days on Human Add AI, three things have changed for the typical operator. First, the recovered-revenue math has compounded into a concrete dollar number that the operator can see in the dashboard and in the bank account. For most single-location service businesses, the first-month recovered revenue lands between $6,000 and $25,000, against a $497 to $997 plan cost. The platform has paid for itself many times over, and the operator mental model has shifted from "evaluating a new vendor" to "operating a critical revenue tool".
Second, the agent has been tuned to the specific cadence of the business. Tuning continues forever (every business evolves, every season brings new call patterns, every new service line needs new intake questions), but the bulk of the agent customization is done in the first 30 days. After that, the operator can edit the knowledge base from the dashboard for most changes and only needs to ping the Human Add AI team for the larger script revisions.
Third, the operator has started thinking about the second-order use cases the platform unlocks. Outbound missed-call callback usually goes live in month two for operators on Professional or Enterprise. Appointment reminder calls usually go live in month three. By month four, the platform is doing both inbound and outbound work that previously required either a part-time staffer or a separate scheduling service, and the operator is running a tighter business with the same overhead.
The honest evaluation timeline
The honest evaluation timeline for an operator deciding whether to install Human Add AI looks something like this. Day zero: call the demo line at (617) 812-5251 from any phone and run a real scenario. The demo takes about ninety seconds and gives a faithful preview of conversation quality. If the conversation quality passes the bar, proceed. If it does not, the operator has saved themselves the rest of the evaluation. Day one: fill out the ten-minute onboarding form. This creates a custom test agent for the specific business, which is free to use during evaluation.
Day two: the Human Add AI team builds the test agent and ships back recorded test calls. The operator listens to the samples, requests any adjustments, and decides whether to proceed. Day three: the operator forwards a test line (a Google Voice number, a secondary business line, or a fresh Twilio number) to the agent and runs a week of real test calls. Day ten: review the test-week data in the dashboard, compare recovered-revenue against the plan price, and decide whether to forward the real business line.
For operators who already know they have a missed-call problem, the evaluation usually collapses into a much shorter window: call the demo, fill the onboarding form, hear the recorded samples, forward the business line. Most operators who go this path are live and recovering missed-call revenue inside 72 hours of first hearing the demo.
