88

Much like the "mailto" URL prefix launches the user's default mail program and starts a new email with specified address, is there a similar URL scheme that would initiate a phone call? Perhaps "phone," "call," or "sip"?

Incidentally, I'm targeting a platform that is using Cisco CUPS, so there may be a platform-specific way for me to initiate a call that is particular to Cisco, but I thought I'd ask the more general question first. However if anyone knows specifically how to programmatically initiate a call via CUPS, that would be great too.

albert
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Jason Marcell
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4 Answers4

105

The official standard for providing a telephone number as a URI is here: http://www.ietf.org/rfc/rfc3966.txt

It basically says use tel: as the prefix, and start the number with +[international dialling code] before the number itself. You can put non-numeric characters as separators (e.g. -) but they must be ignored. So a London (UK) number might be:

tel:+44-20-8123-4567

A New York (US) number:

tel:+1-212-555-1234
rjmunro
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    tel:number also works, but e.g. on Firefox short numbers are recognized as ports. – Nux Feb 06 '14 at 11:34
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    @Nux Do you mean something like tel:123 (which should call the speaking clock in the UK) will be interpreted as http://tel:123/. I'd call that a bug in firefox. – rjmunro Feb 06 '14 at 15:05
13

There is such a URI scheme: tel. It has an elaborate syntax, but here is a simple example of its usage:

tel:123-4567

For the full specification, refer to http://www.ietf.org/rfc/rfc3966.txt .

Julian
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abernier
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11

I'm after the same sort of functionality for Microsoft Office Communicator. After a bit of investigation I found that the following URI syntax will initiate a (VoIP) phone call via communicator: 

tel:+number

eg: to get communicator to call my extension:

tel:+7780
geofftnz
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    `tel:+7780` specifies a globally unique telephone number, including country code, of `7780`. I believe country code `7` is Russia, so that's "Russia 780". I find it unlikely that this is globally unique. If you want to specify a local-context phone number, you have to omit the `+` *and* specify a context. If you want to use `+`, then the phone number specified *must* be fully specified and globally unique. See RFC 3966. – user Aug 04 '16 at 13:11
7

sip: (or sips:) is the official URI scheme for SIP, and I think callto: was used by Skype, but is deprecated.

Simon B.
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instanceof me
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