Call Divert: UK Setup & AI Assistant Tips 2026

Call divert, also known as call forwarding, automatically redirects incoming calls from your phone to another number, such as a colleague's mobile, a landline, or an answering service, so you never miss an important call when you can't pick up. On UK mobiles, one standard no-reply pattern uses \*61*, and across carriers like EE and BT it's often tied to a 15-second unanswered window before the call is redirected.

Interest in call divert usually stems from one of two common situations. You're missing calls and need a quick fix, or you've already switched it on once and now can't remember how to control it properly. For a small business owner, that matters because a missed call isn't just an inconvenience. It can be a booking, a new customer, or a problem a client needs solved now.

What Is Call Divert and When Should You Use It

Call divert sends incoming calls from one number to another when you can't answer on the original line. In practice, that means your business number can ring somewhere else instead of just timing out and dropping into a missed call notification.

A plumber on a job, a consultant in a client meeting, or a salon owner with hands full at reception all run into the same problem. The phone rings at the wrong moment. If nobody answers, the caller may not try again.

That's where call divert helps. It gives the call a second destination and a second chance to be answered.

Why it matters for small businesses

For most small firms, the phone is still a live sales and service channel. Voice hasn't disappeared. In one wider communications trend, talk time on mobile communication apps is projected to reach 71% of total voice traffic by 2025, up from 14% in 2015, which shows voice remains a core fallback channel when people need real contact quickly, according to Boss Revolution's calling statistics overview.

That doesn't mean every business needs a complicated phone system. It means you need a reliable way to keep calls moving when you're unavailable.

Practical rule: If your phone is part of how you win work or support customers, don't let "I'll call back later" be your only process.

Call divert is proactive, not passive

Letting calls ring out is passive. Network voicemail is passive too. Both depend on the caller waiting, leaving a message, and hoping you respond fast enough.

Call divert is different because you choose what happens next.

You can send calls to:

• Your mobile: Useful if you're away from the desk but still available.
• A colleague: Helpful when someone else can take overflow.
• Another site or landline: Good if one location is closed and another is staffed.
• A live answering destination: Better when you want every call answered, not just stored.

If you want a broader picture of how routing fits into business phone handling, this guide to what call routing means in practice is a useful next step.

What Are the Four Main Types of Call Divert

A missed call does not always mean the same thing. Sometimes you are already speaking to a customer. Sometimes your phone is ringing in your pocket while you are with a client. Sometimes there is no signal at all. The four main types of call divert let you decide what should happen in each of those situations.

A simple way to understand them is to treat each type as a different trigger. You are not just forwarding calls. You are setting a rule for when forwarding should happen.

Divert all calls

This is also called unconditional divert. Every incoming call goes straight to the number you choose.

It suits planned situations. For example, you are on holiday, a branch is closed for the day, or you want one central number to answer everything during business hours.

On GSM and UMTS networks, the usual code for this type is \*21*.

Divert when busy

This only applies when you are already on another call.

For a small business owner, this is often the first useful upgrade from basic voicemail. Instead of letting the second caller hit a dead end, you can send them to another person, another line, or a live answering option.

The standard busy divert trigger is \*67* in GSM and UMTS supplementary service codes.

Divert when unanswered

This is the setting many people mean when they say "call divert." Your phone rings first. If you do not answer within the allowed time, the network forwards the call.

That makes it a good fit when you still want the chance to answer personally. If you miss it, the caller still reaches somewhere useful. If you are also trying to stop calls dropping into voicemail too quickly, it helps to understand how to turn off voicemail on your phone before you choose your forwarding rule.

The standard no-reply divert code is \*61*.

Many UK networks that support no-reply forwarding also let you set the ring time before the divert happens, typically in 5-second steps up to 30 seconds. The exact options depend on your carrier and device, so check your network's support guidance if you want to change the delay rather than use the default setting.

Divert when unreachable

This handles calls when your phone cannot be reached at all. Common examples are a switched-off phone, no signal, or a device that is disconnected from the network.

This type is especially useful if you work on the road, visit sites with weak coverage, or spend time in warehouses, basements, or plant rooms. It protects the caller experience when the problem is connectivity, not availability.

The standard unreachable trigger is \*62* in GSM and UMTS networks.

The practical question is not just whether to use call divert. It is which trigger matches the way your business actually misses calls.

That choice matters because the destination matters too. Sending unanswered calls to your own mobile is one option. Sending them to voicemail is another. For many businesses, the smarter setup is to learn these four triggers first, then point the right ones to an AI receptionist so callers reach help instead of a recording.

How to Set Up and Disable Call Divert on Your Phone

A missed call often happens at the worst moment. You're with a customer, driving between jobs, or trying to finish a quote, and the phone keeps ringing. Call divert gives you a simple rule: if you cannot answer here, send the call somewhere else.

On a mobile, you usually set that rule in one of two ways. You either use your phone's call settings, or you dial a short code and press call. For many UK business users, the dial code method is quicker because it talks directly to the network rather than relying on a handset menu that may be labelled differently across devices.

The general dial code pattern

The basic format is straightforward. You dial the code for the type of divert you want, add the destination number, then press call.

For standard GSM mobile networks, the pattern is:

• Activate a divert: \*code\*destination number#
• Example: \*21\*07XXXXXXXXX# then press call
• What happens next: your network saves that rule for incoming calls

That format is widely used by UK mobile networks for call forwarding services. On smartphones, you may also see the same options under Phone, Call Settings, Calling Accounts, or Supplementary Services. If you use a dual SIM phone, treat each SIM as a separate phone line and check the settings for the correct line before testing.

The standard GSM codes to know

These are the main codes used to switch each divert type on:

In practice, UK carriers commonly support these GSM forwarding codes, including \*21*, \*61*, \*62* and \*67* for activation, with matching cancel codes below. The exact menu wording on your phone can differ, but the network-side codes are familiar across EE, O2, Vodafone, and Three business and consumer mobile services.

A good setup routine looks like this:

1. Choose the trigger. Decide whether you want to divert every call, or only calls you miss because you're busy, unavailable, or out of coverage. 2. Choose the destination. Use a number that will be answered, not just another number you might miss. 3. Enter the code and press call. Wait for the network confirmation message. 4. Test from another phone. Check what the caller hears and how long the call rings before it diverts. 5. Check for loops. Make sure the destination number is not set to divert the call straight back again.

The more important decision for many small businesses involves the call's destination. Setting up call divert is the mechanics. Choosing the destination is the business choice. You can send calls to your own mobile, but that often just moves the interruption. You can send them to voicemail, but that still asks the caller to wait and leave a message. A better setup often starts here, with the right trigger, then points calls to a service that can answer them properly.

If voicemail is still catching calls too early, this guide on how to turn off voicemail on your phone can help you tidy up the call flow before you test your divert rules.

How to turn call divert off

Turning call divert off matters just as much as turning it on. A rule set for holiday cover or a busy week can easily stay active longer than you intended.

Use these standard cancellation codes:

• Unconditional off: ##21#
• No reply off: ##61#
• Unreachable off: ##62#
• Busy off: ##67#

If you are not sure which divert is active, use the master reset code ##002# and press call. On UK mobile networks, ##002# clears the common call forwarding settings in one step, which is why it is often the fastest fix when calls start behaving strangely.

A simple way to think about it is this. The activation codes put rules in place. The double-hash codes remove them. If something seems off, clear everything, test again, and rebuild only the divert you need.

Call Divert Destinations Voicemail vs an AI Receptionist

Setting up call divert is only half the job. The bigger decision is where those calls should go.

Many businesses default to the obvious options. They divert to a personal mobile, a colleague, or voicemail. All three can work. All three can also move the bottleneck somewhere else.

Why diverting to another mobile often falls short

Sending calls to your own mobile feels sensible, especially for sole traders. But if you're the person who's already unavailable, you haven't solved the root problem. You've only changed which handset rings.

Diverting to a colleague can help, but only if that person knows they're covering, has the context to answer properly, and isn't already busy.

Many small teams often get stuck at this point:

• One person becomes the fallback for everyone: They get interrupted constantly.
• Calls lose context: The colleague answers, but doesn't know the customer history.
• Coverage breaks outside hours: Nights, weekends, and holidays still go unanswered.

Why voicemail still loses opportunities

Voicemail is better than a dead line, but it asks the caller to do extra work. They have to wait, listen, leave details, and trust you'll call back.

A lot of callers won't.

That's especially true when someone needs a quick quote, a booking, or urgent support. If another business answers live first, that's often where the conversation continues.

Why an AI receptionist changes the outcome

An AI receptionist changes the destination from passive storage to active handling. Instead of recording a message, it answers the diverted call live, greets the caller, understands what they need, and routes the next step.

For small and medium-sized businesses, that's the practical shift. You're no longer asking, "How do I avoid missing calls?" You're asking, "How do I make sure every diverted call still gets handled properly?"

That matters in any language. A modern AI front desk can complement human staff by handling routine enquiries, collecting details, booking appointments, and escalating only the calls that need a person. It doesn't replace your team. It protects their time.

You can see the difference in this comparison of AI receptionist vs answering service approaches.

A better destination usually does four things well:

A diverted call only creates value if someone, or something, actually answers it well.

For a busy organisation, that's why AI is now good enough to complement humans rather than compete with them. People still handle exceptions, judgement calls, and sensitive conversations. AI handles the repeatable front-line work that would otherwise become missed calls, voicemail piles, and manual callback admin.

Call Divert Best Practices and Security for Businesses

A diverted call is a bit like redirecting post. The setting itself is simple. What matters is whether the new destination is correct, available, and safe for the information being shared.

For a small business, the biggest mistakes are usually ordinary ones. A divert gets switched on in a hurry, nobody tests it, and callers start landing on the wrong phone, an unanswered mobile, or a voicemail inbox that nobody checks. Good practice fixes that.

Simple habits that prevent mistakes

Use this checklist:

• Test after every change: Call your main number from another phone and listen to the full journey.
• Tell staff when calls are being sent to them: If a team member becomes the destination, they need to know what types of calls to expect and how to answer them.
• Review active settings regularly: Standard GSM status codes such as \*#21#, \*#61#, \*#62#, and \*#67# can show whether diverts are active on the handset.
• Set a destination that can answer: A diverted call still needs handling. If the fallback is a busy mobile or an ignored voicemail box, the caller's problem has not been solved.
• Plan for patchy signal: In some UK areas, mobile coverage is still inconsistent. That makes "unreachable" divert settings and a reliable backup destination more important, especially for firms that travel, work on-site, or operate from rural locations.

That last point is easy to miss. If your usual fallback is a person's mobile, then your whole call handling process now depends on one battery, one signal bar, and one person's availability. An AI receptionist is often the safer destination because it does not disappear into a meeting, drive through a dead zone, or leave callers waiting for a callback.

Privacy and compliance basics

Call divert itself is only the routing rule. The bigger risk sits at the other end of the line.

If the destination collects names, phone numbers, appointment details, order information, or anything else tied to an identifiable person, your business still needs to handle that properly. The practical questions are straightforward. Who answers? What do they capture? Where is it stored? Who can access it?

For UK businesses, keep these basics in mind:

• Choose a business-ready destination: Anyone or anything answering diverted calls should follow a clear process for handling customer information.
• Check your setup against UK privacy rules: If calls are recorded, transcribed, or used for follow-up, make sure your process fits your lawful basis and communication rules. This guide on AI receptionist use under UK GDPR, ICO, and PECR is a useful starting point.
• Know what is retained: If call details, recordings, or transcripts are stored, confirm how long they are kept and who can view them.
• Limit informal workarounds: Personal mobiles and ad hoc message-taking often create the messiest data trail.

A good rule is simple. Treat call divert as part of your customer contact system, not just a handset setting. Once you look at it that way, the smarter question is not only how to divert calls, but where they should go so the caller gets a prompt answer and your business keeps control of service quality and data handling.

Common Call Divert Questions Answered

A lot of business owners get the setup working, then hit the practical questions. What will it cost? Can you send only certain calls elsewhere? How long does the phone ring before the divert kicks in? Here are the answers that matter in day-to-day use.

Does call divert cost extra

In the UK, the caller pays only to reach your normal number. Your network then handles the second leg of the call, from your number to the number you diverted to.

For you, that usually means the diverted leg is treated like an outgoing call from your phone number to the destination. If you divert to a UK mobile or landline, the charge depends on whether that type of call is included in your plan. If it is not included, you can be charged at your standard rate for that forwarded leg. This is the practical reason frequent diverts to a personal mobile can become expensive, especially for small businesses that receive a steady flow of calls.

The safest approach is simple. Check your plan terms before you rely on divert full-time, and test with a few calls if billing clarity matters.

Will the caller know the call has been diverted

Usually, no.

To the caller, it normally just feels like your call is being answered somewhere else. They may notice a slight pause or a different greeting if the destination answers in a different style, but there is usually no obvious announcement saying the call has been forwarded. That is why the destination matters so much. If a customer rings your business line and hears a rushed personal mobile greeting, the handoff feels messy. If they reach a consistent business answer, the divert feels natural.

Can I divert only some calls

Standard call divert is a network rule, not a contact filter.

In plain English, it works by condition. Send all calls somewhere else, or send calls only when you are busy, do not answer, or are unreachable. It does not usually let you say, "divert supplier calls one way and customer calls another way" using the basic handset or carrier divert feature alone.

If you need that kind of selective handling, you are moving beyond simple call divert and into business call routing. That is often the point where sending calls to an AI receptionist makes more sense than sending them to one mobile phone. The call is still diverted, but the destination can answer consistently, collect details, and route the caller properly instead of depending on one person being free.

Can I set a delay before unanswered calls divert

Often, yes.

The unanswered-call divert setting is usually the one tied to a ring delay before the call forwards. On many phones, this is handled through the no-reply divert code, commonly using *61* with the destination number. The exact delay options depend on your phone and network support, but in practice UK users will often see a short ringing window before the call moves on.

If you are unsure, test it like you would test a shop doorbell. Ring your business number from another phone, count the seconds, and see when the divert happens. If the delay is too short, callers can feel rushed. If it is too long, they may hang up before anyone answers. For many businesses, the better fix is not only adjusting the timing. It is sending the call to a destination that answers reliably every time.

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Diverting calls only helps if someone answers usefully at the other end. An AI receptionist like fonea answers diverted calls live, day or night, instead of letting them drift to voicemail or a personal mobile. If you want to see how that fits your business, check the pricing.