EE
O2
Vodafone
Three
giffgaff
Sky Mobile
SMARTY
Talkmobile
iD Mobile
Asda Mobile
Virgin Mobile
Conditional call forwarding explained
Conditional call forwarding redirects a call only when something is true: you did not answer, you were already on a call, or your phone was off. Your phone rings first and the redirect happens afterwards. Unconditional forwarding — the all-calls kind — redirects every call immediately and your phone never rings at all. Almost everything useful you can do with forwarding on a business line is conditional.
Last reviewed
The three conditions
No reply, code 61. The call rings your handset for the network's ring timeout — usually around 20 seconds — and if nobody picks up, it is redirected. This is the one that replaces voicemail, and it is the one a business almost always wants.
Busy, code 67. The call is redirected because you are already on another call. Worth setting alongside no-reply if you take calls back to back, since otherwise a second caller during a long call gets voicemail even though your no-reply rule is set.
Not reachable, code 62. The call is redirected because your handset is off, has no signal, or is in flight mode. This is the one that keeps working when you are down a cellar or on a site with no coverage.
Why conditional is the one you want
Unconditional forwarding takes your phone out of the loop entirely. You stop receiving calls. For a business number that is almost always wrong: you want to answer the calls you can, and you only want a fallback for the ones you cannot.
Conditional forwarding is invisible on every call you answer. Pick up as normal and nothing about the call is different — no delay, no extra ring, no third party involved. The rule only exists for the calls that would otherwise have gone nowhere.
It also means the fallback cannot accidentally swallow your business. If your forwarding destination breaks, you still get your calls, because the handset still rings first.
Setting all three at once
**004*number# registers the same destination against all three conditional rules — no reply, busy and unreachable — in a single code, and ##004# cancels all three. It is the tidiest way to cover every case where you did not take the call, without touching the all-calls rule.
The catch is the ring time: the combined code does not let you specify one, so you get the network default. If you need a specific ring time before forwarding, set the no-reply rule on its own with **61*number**seconds#.
The rules are independent. Setting one does not clear the others, which is the usual reason a line ends up behaving unexpectedly — an old all-calls divert sitting underneath a new no-reply one. *#21# will tell you if that is what has happened.
The ring time before it forwards
The network waits a fixed period before deciding a call is unanswered. Around 20 seconds is typical in the UK, which is roughly five or six rings. Some networks let you set it in five-second steps up to thirty; others ignore the request and keep their default.
Shorter is not always better. Set it too short and calls forward while you are still reaching for the phone. Set it too long and the caller has given up before the redirect ever happens. The default is a reasonable compromise, and it is worth changing only if you have a specific reason.
Common questions
Forwarding that only happens when a condition is met — the call was not answered, the line was busy, or the handset was unreachable. Your phone rings first, and the redirect happens only if you do not take the call.
Unconditional forwarding, set with **21*, redirects every call the moment it arrives and your phone never rings. Conditional forwarding lets the call ring you first and only redirects it if you do not take it.
Yes, and they are independent. Set them individually with **61*, **67* and **62*, or all three at once with **004*number#. Setting one does not cancel the others.
Around 20 seconds on most UK networks, which is about five or six rings. Some networks let you choose in five-second steps with the **61*number**seconds# form, and some ignore the request entirely.
Not at all. Answer the call and nothing about it is different — the rule only ever applies to calls that were not taken.
Related guides
Setting it up on your network
The codes above are the standard GSM ones and work the same way everywhere. Where networks differ is in what they accept, what their handset menus are called, and what they do after a SIM swap.
Or stop losing the calls entirely
Point unanswered calls at TextTheCaller and every caller gets a text from your business name within seconds.
7 days free, then £6.49/mo. Cancel any time.