Callto or tel?
When creating my online resume, I wanted to make my telephone number clickable to enable easy calling from a mobile device or VOIP phone. However, it doesn’t seem that there is a universally accepted way of doing this.
My first thought was to use the tel URI to create a link like this. However, while this is technically the correct way of doing it (as specified by RFC 3966 and RFC 5341), major VOIP apps like Skype do not seem to recognize it. Instead, Skype decided to go their own way and use the callto: handler for phone numbers, so I can’t have one easily clickable link that will work on phones and Skype.
As computing devices become further consolidated, I think this will become more of an issue. I ended up having two separate links, one using the tel handler and another using Skype’s callto handler, or with the skype: handler if you have an associated Skype account.
While you can easily use third-party browser plugins like Telify to convert phone numbers to links for you, non-standard URIs like callto: help nobody and only serve to make things more difficult for everybody. I’d much rather use tel links if possible.