91

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.

Improve this question

4 Answers 4

Reset to default
109

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
Improve this answer
2
  • 1
    tel:number also works, but e.g. on Firefox short numbers are recognized as ports.
    – Nux
    Commented Feb 6, 2014 at 11:34
  • 8
    @Nux Do you mean something like tel:123 (which should call the speaking clock in the UK) will be interpreted as tel:123. I'd call that a bug in firefox.
    – rjmunro
    Commented Feb 6, 2014 at 15:05
14

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 .

Improve this answer
0
10

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
Improve this answer
1
  • 10
    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
    Commented Aug 4, 2016 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.

Improve this answer
3
  • 20
    "Callto" was discarded because URI schemes locate a resource and do not specify an action to be taken.
    – Richard Ayotte
    Commented May 8, 2013 at 22:15
  • 2
    SIP is deprecated because tel: is more general.
    – Leandro
    Commented Sep 22, 2020 at 23:14
  • skype://myskypename worked for me
    – vkersten
    Commented Mar 11, 2023 at 12:17

Not the answer you're looking for? Browse other questions tagged or ask your own question.