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.
Human Add AI charges $497, $997, or $1,997 per month depending on the volume tier, with outbound calling metered at fourteen cents per minute on top of the Professional and Enterprise plans. There is no setup fee, no annual contract, no per-seat charge, no per-lead charge, and no per-call charge on inbound. The platform is intentionally priced to be a flat monthly line item that an operator can compare directly against the cost of a virtual receptionist service or the salary of a part-time in-house front desk.
The Starter tier is the right entry point for most operators. It covers a single location, up to 250 inbound calls per month, and the full conversation engine. The 250-call cap maps to a typical service business doing roughly 50 to 60 inbound calls per week. Operators expecting much higher volume should price the Professional tier, which raises the cap to 750 inbound calls per month and unlocks the multi-location routing and the CRM-deep-integration matrix.
Professional at $997 monthly is also the tier where after-hours emergency escalation routing becomes standard, where the CRM integration set covers Jobber, Housecall Pro, ServiceTitan, FieldEdge, mHelpDesk, Workiz, Salesforce, HubSpot, Pipedrive, Clio Manage, Lawmatics, MyCase, PracticePanther, Dentrix Ascend, Open Dental, Eaglesoft, Curve Dental, ServiceM8, RazorSync, and twenty other vertical-specific systems, and where the SLA-backed response time on agent tuning tightens.
Enterprise at $1,997 monthly is for operators who want the volume cap removed entirely, the dedicated agent-tuning contact, the white-label phone numbers, the on-call dispatcher priority routing, and the outbound module. The outbound module unlocks four use cases at the same fourteen-cents-per-minute rate: missed-call callback (the highest-ROI use), appointment reminders (24 hours before the booked time), post-service review collection, and lead nurture for prospects who asked for information but did not book on the first call.
Questions operators ask before signing up
How is the call quality measured?
Three quality signals get tracked on every call. The first is conversation completion: did the agent successfully complete the intake or did it transfer to a human. The second is booking conversion: of completed calls, what percentage resulted in a booked appointment. The third is post-call sentiment: a brief categorization (positive, neutral, negative) based on the caller's word choice during the conversation. All three roll into the weekly summary, with per-call detail in the dashboard.
What happens when a caller asks for a price?
The agent quotes the prices the operator entered during onboarding (flat rates, hourly rates, service-specific ranges). For services where pricing depends on a site visit or a custom scope, the agent says so explicitly and offers to book the free estimate. The platform never invents a price the operator did not provide, which protects both the operator from underquoting and the customer from over-promising.
Does the agent handle Spanish or other languages?
The agent handles Spanish natively at no extra cost. The caller can switch language at any point in the conversation; the agent picks up the language change automatically. Other languages (Vietnamese, Mandarin, Portuguese, French, Korean, Arabic) are available on the Professional and Enterprise tiers with onboarding-time setup. The booking confirmation SMS and the lead alert SMS go out in the caller's preferred language.
What if my call volume spikes?
The platform handles concurrency without queuing. Every inbound call gets its own agent instance, so 25 callers dialing simultaneously each get answered in two rings without any of them hearing hold music or a busy signal. The pricing tier governs monthly call volume, not concurrent-call capacity. If a tier's monthly cap is exceeded, the platform keeps answering calls and the dashboard surfaces an upgrade recommendation; calls are never dropped at the tier boundary.
How is missed-call callback different from outbound calling?
Missed-call callback is a specific outbound use case where the agent calls back any caller who hung up before reaching the agent (usually within 90 seconds). It is enabled by default on Professional and Enterprise. General outbound calling is broader (appointment reminders, lead nurture, review collection, post-service follow-up) and is billed at fourteen cents per outbound minute on a transparent meter. The missed-call callback uses outbound minutes but operators rarely cap it because the ROI on a missed-call callback is the highest of any outbound use case.
Do I have to switch my existing phone number?
No. The forwarding model preserves the existing business number entirely. The caller dials the same number they always dialed; the carrier silently forwards the call to the Human Add AI number behind the scenes; the agent answers. The caller-facing number, the existing phone listings, the Google Business Profile, and any print marketing all stay exactly the same.
How does it handle existing customer calls vs. new lead calls?
The agent recognizes existing customers via the inbound number lookup against the CRM. When a known customer calls, the agent greets them by name (using the CRM record) and routes the conversation to the appropriate path (existing-customer support questions, follow-up scheduling, billing questions). New leads get the full intake script. The split is configured during onboarding and adjustable from the dashboard.
What does the support team look like?
A real human at Human Add AI responds within four business hours on Starter, within two business hours on Professional, and inside one business hour on Enterprise. Support covers script edits, integration questions, billing questions, and any urgent issue with the live agent. The support contact is the same human who built the agent during onboarding, which means no ticket-handoff between front-line support and engineering.
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.
