Have you been blocked by an iPhone using iOS 7? One of the simplest but most convenient new features in iOS 7 - the latest version of Apple's operating system software for iPad, iPhone and iPod touch - is the ability to easily block the phone numbers of nuisance callers. (We explain how this works in 'How to block a number on any iPhone, in iOS 7 and iOS 6') Updated, 15 May 2014

This is great news for those who are plagued by calls from salesmen or drunken ex-boyfriends. But what if you're on the receiving end? How can you tell if someone has blocked you on iOS 7?

The simple - and sad - answer is that you can't easily find out for sure - but there are clues. We blocked one of our other phones to find out exactly what it's like to be blocked, to help us work out when we've been blocked in the future.

If you'd rather watch our experiment than read about it, however, have a look at this:

What happens when you ring someone who's blocked you?

We rang the iPhone that had blocked us. The phone rang exactly once, and then we were told that the number was unavailable. Then we were invited to leave a message. (Note that the iPhone never received any notification that this message had been left. But the blocker can access these messages if they choose to go into their voicemail and scroll down to the 'Blocked Messages' folder. Thanks to reader 'Kat' for bringing this to our attention.)

A single ring and then being diverted to voicemail is the giveaway behaviour you're looking for - but this can also result from the phone being switched off or set to auto divert. 

To rule these out, you can immediately ring again from a different number, or disguise your number using the relevant code for your country (141 from a UK landline, for instance), or by switching off your call ID in the settings if you're using an iPhone (Settings, Phone, Show My Caller ID, switch to off).

This time your number won't be visible and any block on that number will be bypassed. If the phone really is switched off or set to divert, it will once again ring once and then go to voicemail. But if you were blocked, either the person will pick up, or it will ring a few times until you ring off or they turn down the call because there isn't a caller ID they recognise.

Thanks to our reader, posting below under the name 'This is true', for coming up with this cunning scheme.

And what happens if you text someone who's blocked you?

What about if you send a text to the 'blocker'?

We tried to send a text message to the phone that had blocked us. Everything proceeded as usual - the text sent, and we got no error message. But the 'receiver' didn't get any message, or any notification.

But a clever reader, Vickie Humphrey, has thought up a way to get more clues - try to send the text as an iMessage.

"The way to tell if you've been blocked," Vickie explains, "is by checking to see if your iMessage says 'Delivered'. You've been blocked if it doesn't, and after a good few minutes, it sends as a text message. Which is never actually being received."

iPhone 5s

How to tell if someone has blocked your phone number on iOS 7

So. Other than the obvious clues - you never seem to be able to get through to someone, despite ringing at various times and checking that you've got the right number - the main giveaway is the way you get diverted to voicemail after exactly one ring. If your call is manually declined, or if they're just not available, then you'd expect the phone to ring several times before you're diverted.

If you're getting a single ring before being diverted to voicemail, and then when you try again with caller ID hidden you get a different response (multiple rings and then declined or diverted, or they pick up) then something is probably up.

Finally, Vickie's clever iMessage trick is a useful way of seeing if you've been blocked, assuming you're calling from an iPhone.

Remember that just because you are allowed to leave a message - or because your text seemed to go through without any problems - that doesn't put you in the clear. The blocking process is quite sneaky about letting you (the caller) know what's happened.

As we said, though, there's no way to be sure this is what's happened, so be careful before you start throwing around accusations! And if any amateur sleuths out there work out a foolproof method of finding out if you've been blocked, let us know in the comments or via Twitter. Our thanks to the clever readers who've already contributed techniques for cracking the mystery.

How to tell if someone blocks your number on iOS 7

How to call someone anyway, even though they've blocked you

Yep, as discussed briefly above, it's possible to hide your caller ID (or use a code to stop it from being revealed) and thereby call someone who's blocked you. We take no responsibility for the legal and social consequences of doing this - it's an emergencies-only strategy that some would consider harassment - but we're written a tutorial showing How to call someone who has blocked you.

Get your own back: How to block a number using an iOS 7 iPhone

This is all very upsetting, of course, but call-blocking is actually a very useful feature of iOS 7. If you're getting calls from a persistent telesalesman or infatuated ex - or you want to take revenge on the person we've been talking about in this tutorial - then it's easy for you to make use of the feature yourself. And now you know what they'll be experiencing.

You can easily block a number from the Recent Calls menu. Check out the process in our tutorial 'How to block a number on any iPhone, in iOS 7 and iOS 6'.

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