How to Set Up an AI Receptionist: Forwarding Your Calls, Step by Step
How to Set Up an AI Receptionist: Forwarding Your Calls, Step by Step
The agent is configured, it knows your services and opening hours, and it sounds good in testing. That leaves the question most rollouts actually get stuck on: how does a call to your normal business number reach the agent in the first place?
The answer is call forwarding — the same feature that has been sitting in every phone network for decades. You need no new number, no porting and no new hardware. This piece covers which kind of forwarding suits which business, how to set it up on mobile, on a landline, on a router with a built-in phone system, and in a cloud PBX, and how to check that it actually works.
The short version
- Your existing number stays. Calls get forwarded, not replaced.
- There are four kinds of forwarding. The interesting one is on no answer — the agent steps in only when nobody picks up.
- On mobile, the GSM standard codes work across networks; you dial them like a phone number.
- On a landline and on a router, it runs through star codes or the device’s menu.
- After setting it up, call in yourself — from someone else’s line, not your own second handset.
If you are earlier in the process and want to know what an agent like this does at all, that is in what is an AI voice agent.
The four kinds of forwarding — and which one you want
Make this decision before you type anything. It matters more than any code.
| Kind | When it triggers | What it is good for |
|---|---|---|
| Unconditional | Always. Your phone never rings | When the agent should take every call first |
| On no answer | After x seconds of ringing | The normal case: humans first, AI as the safety net |
| On busy | When you are already on a call | So second callers are not lost |
| On unreachable | No signal, phone off | Mostly relevant on mobile |
For most businesses the right answer is a combination: on no answer after roughly 15 to 20 seconds, plus on busy and on unreachable. Your team stays the first line, and no call falls through when nobody can pick up.
Two situations argue for unconditional forwarding: you deliberately want the agent to triage first and put only certain requests through — or you forward only outside opening hours, switching it on in the evening and off in the morning.
On ring duration: below 10 seconds the forward fires before anyone can realistically answer. Above 25 seconds many callers hang up first. Fifteen to twenty seconds is about four or five rings and makes a good starting point.
Mobile: the standard codes
Mobile networks have had fixed key sequences for this since the early days of the GSM standard. They work across networks and across most operators. You type the sequence into the dialler and press call; the phone then confirms whether it worked.
Replace TARGETNUMBER with your agent’s number, in international format with the country code.
Forward on no answer (the recommended default)
**61*TARGETNUMBER**20#
The 20 at the end is the ring duration in seconds. Values from 5 to 30 in steps of five are usually accepted.
Forward on busy
**67*TARGETNUMBER#
Forward when unreachable
**62*TARGETNUMBER#
Forward everything immediately
**21*TARGETNUMBER#
Check the status
*#61# *#67# *#62# *#21#
Switch off
##61# ##67# ##62# ##21#
To clear all conditional forwards at once: ##004#.
One practical tip: set 61, 67 and 62 together. Setting only one of them is the most common mistake — the agent then catches unanswered calls, but the caller who hits a busy tone is still lost.
Landline: star codes
On landlines the same cases run through star codes you enter on the connected handset. The scheme is broadly consistent across networks:
- Forward immediately:
*21*TARGETNUMBER#— cancel with#21# - On no answer:
*61*TARGETNUMBER#— cancel with#61# - On busy:
*67*TARGETNUMBER#— cancel with#67#
After entering it you usually hear a confirmation tone or announcement. On some lines you also have to press the call button; on others the entry alone is enough.
Whether your line supports delayed forwarding, and how the ring duration is set, depends on the operator. That is the point to check your provider’s help pages or make a short call to support — it is a question they answer in two minutes.
Routers with a built-in phone system
If your telephony runs through a router with a built-in phone system, you set forwarding up in the device’s interface rather than on the handset. That is the more comfortable route, because you can maintain several rules side by side.
In current firmware the path runs through the telephony section and from there to call handling or call forwarding. A rule takes three pieces of information: which incoming number it applies to, under what condition it fires (immediately, on busy, after a delay), and where the call goes — your agent’s number.
The advantage of this route: you can combine several rules and treat individual numbers differently. With two numbers, one can go straight to the agent while the other keeps ringing internally.
Because menu labels move between firmware versions, the same applies here as above: if the wording differs on your device, searching your manufacturer’s help for “call forwarding” gets you there faster than any external walkthrough.
Cloud PBX
If you run a cloud PBX, forwarding is an entry in the admin portal — usually under call handling, call rules or something similarly named. This gives you the most options: forwarding by time of day, by weekday, by queue length, or as the final step of a ring group after several extensions have rung without an answer.
That last variant is the most elegant for many businesses: the team rings first, and the agent sits at the end of the chain. More on how this fits with conventional telephony in AI phone system.
After setup: the test almost everyone skips
A forward you have not tested is a guess. Check these five things, and do it from someone else’s line — a call from your own second device sometimes behaves differently.
- No answer. Call and let it ring without picking up. Does the agent come on, and after how many seconds?
- Busy. Take a call and have someone else ring in at the same time. Does the second caller reach the agent?
- The disclosure. Does the agent say in its first sentence that it is an AI system? That is not a matter of style — in the EU it has been an obligation under Article 50 of the EU AI Act since 2 August 2026. Detail in the AI disclosure obligation.
- The route back to a human. In the test call, say you would like to speak to a person. Does it transfer cleanly, and whose phone rings?
- Caller ID on callbacks. Call back out of the system — does your business number appear, or an unfamiliar one? That decides whether customers pick up your callbacks.
When it does not work
The forward is rejected. Usually the target number is in the wrong format. Use the international format consistently, with the country code and no spaces.
It keeps ringing without forwarding. Check with *#61# whether the rule is set at all. On some contracts conditional forwarding is blocked by default and has to be enabled by the operator.
Callers land in voicemail instead of at the agent. Voicemail is itself a forward and occupies the same condition. Switch voicemail off for that condition, or it wins.
It forwards too early. Increase the ring duration — for 61, through the value at the end of the code.
It behaves differently abroad. Forwarding on “unreachable” reacts differently while roaming. If your business depends on that case, test it separately.
What the caller experiences
Very little, when it is set up properly. They dial your familiar number, it rings a few times, and then the agent answers with your business name. From the caller’s side it looks like somebody picked up — which is exactly the point, because the alternative until now was that nobody did.
Two things are still worth deciding deliberately. First the greeting: it should include your business name, so it is clear the call arrived where it was meant to. Second the transfer rule: when does the agent hand over to a person, and to whom? An agent without a defined boundary is the most common cause of bad experiences — more on that in is an AI phone agent worth it for small business.
Codes and menu paths as described are current as of September 2026. The GSM codes are standardised and stable; menu paths in router and operator portals change with new versions. Check your provider’s help pages if in doubt.
Frequently Asked Questions
How do I set up an AI receptionist? In two steps. First configure the agent itself — services, opening hours, greeting, transfer rules, calendar connection. Then forward calls from your existing number to the agent’s number. The second step takes a few minutes; the first is what determines quality.
How do I activate call forwarding?
On mobile, through the GSM standard codes: **61*TARGETNUMBER**20# forwards after 20 seconds of ringing, **67*TARGETNUMBER# on busy, **21*TARGETNUMBER# immediately. On a landline the same cases run through *61*, *67* and *21*. On a router or cloud PBX you create the rule in the interface instead, under telephony or call handling.
Can I keep my existing phone number? Yes, and that is the usual route. The number stays with your current operator; calls are simply forwarded. Porting is not needed and usually not worth it.
Can I see who called when the call was forwarded? Yes. The original caller’s number is normally passed along, so your call log shows who rang even though the call arrived via the forward. If the caller withholds their number, that behaves as it would on any other call.
What happens to voicemail? Voicemail is itself a forward and competes with your new rule for the same condition. If callers keep landing in voicemail despite your setup, switch it off for that case.
After how many seconds should it forward? Fifteen to twenty seconds, which is roughly four or five rings. Shorter takes away your team’s chance to answer; longer loses callers.
Does call forwarding cost anything? That depends on your contract. On some plans domestic forwarding is included; on others the forwarded leg is billed like an outgoing call. Ask your operator before you set it up — it is the only item in this process that can surprise you.
Can I forward only outside opening hours? Yes. On a cloud PBX or a router with a phone system you can schedule it. On plain mobile without such a system you would switch it on and off manually — in which case the combination of no-answer and busy forwarding is usually the more practical solution.
Set up the agent, then connect the number
If the first step is still ahead of you: you can create an agent for free without a credit card, give it your services and opening hours, and call it before you change any forwarding at all. Which calendars and systems can be connected is on integrations.
Related Articles
- What is an AI voice agent? — fundamentals and mechanics
- AI phone appointment booking — what happens after the call is answered
- AI phone system — how this fits with conventional telephony and IVR
- The AI disclosure obligation — the notice that belongs at the start of the call
- AI receptionist comparison — criteria for choosing a provider