Call forwarding from a landline: codes and how to set it up
Call forwarding lets a business keep its number and change who answers. On mobile phones it is set from the phone's menu or with the standard GSM codes (for example **21*number# to forward every call); on landlines each carrier uses its own codes, and in Italy TIM, Fastweb and WindTre all start from *21*number#. It is also the simplest way to have an AI phone assistant answer your calls: customers dial the usual number and the line passes the call on, always or only when nobody picks up.
This guide covers the four types of forwarding, the codes for mobiles and for the main Italian landline carriers, what it costs, which setup suits which kind of business and how to connect your number to an AI assistant.
Why forward instead of changing number
Your business number is on your cards, your Google profile, booking sites and shop sign. Changing it costs time and customers. Forwarding leaves all of that alone.
Landlines are far from gone, either. In Italy, according to AGCOM's Communications Observatory no. 2/2026, there were 20.45 million fixed-line accesses in March 2026, up 0.6% year on year, and only 10.2% of them were still copper.
The four types of call forwarding
| Type | When it kicks in | Mobile (GSM standard) | Italian landline (TIM, Fastweb) |
|---|---|---|---|
| Unconditional | Always: your phone doesn't ring | **21*number# | *21*number# |
| Busy | When you are already on a call | **67*number# | *22*number# |
| No answer | After a few unanswered rings | **61*number# | *23*number# |
| Unreachable | Phone off or no signal / line down | **62*number# | *24*number# (TIM) |
Mobile codes come from the GSM specification (ETSI TS 122 030) and are the same with every carrier. Landline codes are not standardised: they vary by carrier and country, and some lines only offer unconditional forwarding.
On a mobile phone
- From the menu: in the Phone app settings, under Call forwarding. On iPhone you set forwarding for all calls; on Android you can usually pick the case (always, busy, no answer, unreachable).
- With GSM codes: **61*number**20# forwards calls you don't answer within 20 seconds (the standard allows 5 to 30 seconds), *#21# shows the active forwarding, ##002# cancels everything.
Always type the destination number in full, with the country code (for example +39 for Italy).
On an Italian landline
- TIM: on fibre, FTTC and ISDN lines forwarding is included and uses *21* (all calls), *22* (busy), *23* (no answer) and *24* (line unreachable), each followed by the number and #; #21#, #22#, #23#, #24# turn them off (TIM support). On old copper lines it is requested from TIM customer service, carries a monthly fee and is unconditional only.
- Fastweb: same *21*, *22*, *23* codes, also configurable from the MyFastweb customer area. Activation is free; the support page lists 5 cents for a forwarded call, even with calls included in the plan.
- WindTre ("In Trasferta"): *21*number# to turn on, #21# to turn off, *#21# to check; depending on the line it is already active or must be requested (WindTre).
- Vodafone lists the standard codes on its call forwarding page and notes that call waiting must be off for busy forwarding; for a landline, check with support which codes your router accepts. Iliad lists forwarding to national numbers at 5 cents a minute in its fibre price list.
Codes and prices change: check your carrier's page or contract before turning forwarding on for a business line.
If you have a phone system
With a VoIP phone system or PBX you don't forward from the handset: you add a forwarding rule in the system's admin panel, usually by time of day or for extensions that don't answer. If the system uses a SIP trunk, the assistant can also be connected to the trunk directly. See our telephony integrations and the guide on AI phone systems vs IVR.
Which type to choose
- Restaurant: nobody can leave the floor during service. Unconditional forwarding at peak times and no-answer forwarding the rest of the day catch the bookings you would otherwise lose. See restaurants.
- Medical or dental practice: reception answers while it can, then the line is busy. Busy plus no-answer forwarding work well together. See medical practices.
- Workshop or shop: hands are full and the phone rings out. No-answer forwarding keeps the calls you can take; on a mobile you can choose the delay. See auto repair shops.
- After hours: unconditional forwarding turned on at closing and off at opening. A phone system can schedule it; on a plain landline you use the code each time.
How to connect your number to an AI assistant
With an AI phone assistant like yourang.ai:
- Copy the assistant's number from the dashboard, in full, with the country code.
- Choose the forwarding type that matches when you miss calls.
- Turn it on with your carrier's code, from the phone menu or in the phone system panel.
- Test it by calling your number from another phone: the assistant should answer.
- Decide when the assistant hands over to a person, with transfer rules to an extension or a mobile, for urgent calls or callers who ask for someone.
If the call doesn't arrive, the usual causes are a missing country code, forwarding not active on the line, or a plan that blocks forwarding to some numbers: that's one for your carrier. If you'd rather not touch your line at all, you can use a new dedicated number instead.
Checklist
- I know my carrier and line type (fibre, copper, phone system).
- I've checked the codes and the cost of forwarded calls on my carrier's page.
- I've picked the forwarding type for the hours when I miss calls.
- I've typed the destination number in full, with the country code.
- I've made a test call from another phone.
- I know how to turn it off.
For what happens to the call once it reaches the assistant, read our guide to the AI answering service. To hear it handle your own questions, book a demo; plans are on the pricing page.
Frequently asked questions
What is the code to forward calls?
On mobile phones the GSM standard codes work with every carrier: **21*number# forwards all calls, **67*number# when busy, **61*number# when you don't answer and **62*number# when the phone is unreachable; ##002# cancels them all. On landlines each carrier sets its own codes: in Italy TIM, Fastweb and WindTre use *21*number# to forward all calls and #21# to turn it off.
Who pays for a forwarded call?
The line that forwards it. The caller pays for the call to your number as usual; the leg from your number to the destination is charged to you according to your plan. Check your carrier's price list before you turn it on.
Can I forward calls only when I don't pick up?
Yes, with no-answer forwarding: your phone rings first and, if you don't answer, the call moves on. On mobiles you can usually set the delay from 5 to 30 seconds. Some older landlines only offer unconditional forwarding.
Does forwarding to an AI assistant change my phone number?
No. Customers keep calling the same number and your carrier passes the call to the assistant's number. To go back, you simply turn forwarding off.
Why isn't call forwarding working?
The usual causes are a destination number typed without the country code, a forwarding service that is not active on the line, or a plan that doesn't allow forwarding to some numbers. Call your own number from another phone to test it.
