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iPhone Telephone Hyperlinks

Enough with the iPhone news. Let's talk about a little detail that no one else is talking about. The interesting thing for me is how the web is joining our good friend the telephone. A while back I talked about Callto links and how these could be tied into Vonage using a little tool I wrote. So I was pretty interested to see how the iPhone would allow a web-page to connect to a telephone number.

i was expecting either callto: links or perhaps a telephone microformat or perhaps a proprietary solution.

Surprisingly it turns out that it's none of the above. The iPhone is using a not so well known RFC to create telephone hyperlinks. This is done through a tel: link format that I'd never heard of called RFC 3966.

The format allows you to create an anchor link and use a tel: URI to point to a telephone number. For example if you wanted to contact Apple customer support you would use a link like this:
Call Apple Customer Support at 1-800-275-2273
Go ahead and give it a try, I don't yet have an iPhone to test this out.

The link format is fairly straight forward:
<a href="tel:+1-800-275-2273">
Call Apple Customer Support at 1-800-275-2273

If more sites start using this for their contact information other providers for the tel: URI may begin supporting the format (Vonage, Verizon, Skype, etc.) This makes it easy to transition from a web interface to a voice interface. The format also theoretically suppors alternative SIP providers and extensions making it possible to put a corporate directory online in the form of an iPhone application.

Update:  Apple also supports turning off auto-detection of phone numbers via a meta-tag.

<meta name="format-detection" content="telephone=no">

Update 2:  When I first wrote this post we hadn't done any real iPhone work. I didn't even own an iPhone. Since then a lot has changed, our company now focuses on building world class apps. Learn more from our homepage and let me know if we can help.

This post is licensed under CC BY 4.0 by the author.