Call blocking was one of the simplest but most convenient new features added to iPhones as part of the iOS 7 update back in 2013. We explain how this works in our guide on how to block a number on any iPhone.

Apple kept the feature for later updates, including the most recent iOS 10 and the upcoming iOS 11, so the vast majority of currently active Apple smartphone can prevent nuisance callers from getting through if they choose.

This is great news for those who are plagued by calls from persistent telephone salesmen and other pests. But what if you're on the receiving end? How can you tell if someone has blocked you?

In this article, we explain the telltale signs: the way your phone behaves as you (unsuccessfully) try to get through, what response you'll get as you call, text and attempt to leave a message, the giveaway number of rings before you're diverted to voicemail and so on. We'll help you work out if someone has (for whatever reason) blocked you.

What happens when you ring a phone that's blocked you?

What happens when you ring a phone that's blocked you?

We blocked one of our spare phones to find out the number of times a call will ring before being declined or sent to voicemail, the response when sending a text and so on, all of which will help us work out when we've been the victims of this feature in the future.

We rang the iPhone that had blocked us. The phone rang exactly once, and then we were told that the number called wasn't available, diverted to voicemail and invited to leave a message. Note that the iPhone never received any notification that this message had been left.

As an aside, even though the recipient gets no notification that a message has been received, they do get the message and can listen to it if they choose.

If a blocked caller has left a voicemail on your phone, you can access it by going into your voicemail and scrolling down to find the 'blocked messages' folder, which will sit below the 'deleted messages' folder. Note that if you've not had any such messages the folder itself won't be visible. And there will be a delay between the person leaving the message and it appearing in the folder.

A single ring and then being diverted to voicemail is the giveaway behaviour you're looking for - but bear in mind that this can also result from the phone being switched off or set to auto divert. So we'll rule those out next.

Ruling out other possibilities

Ruling out other possibilities

To rule out the phone being switched off or set to auto divert, 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 call ID in the settings if you're using an iPhone (Settings > Phone > Show My Caller ID, then switch it 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.

What happens when you text a phone that's blocked you?

What happens when you text a phone that's blocked you?

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.

When sent as an iMessage, the text gave us a 'Delivered' notification and remained blue - our blocked iPhone didn't attempt to send it as an SMS.

Remember that just because your text seemed to go through without any problems, that doesn't mean you haven't been blocked. The feature is quite sneaky about letting you (the caller) know what's happened.

As we said, though, there's no way to be certain this is what's happened, so be careful before you start throwing around accusations!

The other possibility: Do Not Disturb

The other possibility: Do Not Disturb

There is, of course, another possibility. Your friend may not have blocked you; they may have just activated Do Not Disturb mode and thus, on a temporary basis, effectively blocked everyone.

If they are using Do Not Disturb mode, the potential solutions and workarounds are slightly different to the ones you use to get round a user-specific block. To find out more, read how to tell if someone is using Do Not Disturb mode.

How to call someone even though they've blocked you

How to call someone even though they've blocked you

As discussed briefly above, it's possible to hide your caller ID and thereby call someone who's blocked you. Software-level call blocks can only work if they know what number is incoming - this is true across all smartphone software, and the only way to block someone who hides their caller ID is to contact your phone company.

If you're in an emergency, or there is some other exceptional circumstance that you feel justifies doing so, you can bypass a call block in this way, but please bear in mind that the recipient of the call may consider this behaviour to be harassment or stalking, and there could even be legal ramifications. This is not something that you should do lightly.

If you have taken all of these warnings on board, take a look at our tutorial showing how to call someone who has blocked you.