So let’s just say that convergence, whatever that is, has happened and we all have beautifully coded, semantic portals that are able to scale and deploy themselves to any delivery context. Let’s further assume that someone is browsing your testament to seamless interactive and wants to congratulate on your creation the old fashioned way…by calling you.

How do they do that? By looking at a sequence of numbers on their screen and manually inputting them into their telephony device? How barbaric… You might as well make your users learn Morse code. The truth is convergence hasn’t happened, and one of the indicators of that is that there still is no good/standardized cross-platform method of hot linking phone numbers.

The current vogue method of linking phone numbers is the method described in RFC 3966, and is also the method which Apple recommends for constructing iPhone phone links. Example:

<a href="tel:+44-1386-871490">Call GJB Enterprises</a>

The iPhone, and several other mobile browsers, also attempt to parse pages and automatically construct links to what it believes to be phone numbers and automatically link them. Unfortunately this often results in the linking of dates and baseball statistics. Browsers are also beginning to support a depreciated form of RFC 3966 in order to allow for text message functionality:

<a href="sms:+44-7785-372422">Text GJB Enterprises</a>

We can also see the roots of RFC 3966 in the Voice XML (VXML) implementation of “call transfer”:

<form id="CallTransfer"><transfer name="MyCall" dest="tel:+44-1386-871490" bridge="true" ></transfer>

For the most RFC 3966, and its depreciated forms, work as intended on mobile platforms and have replaced the WAP/WML Wireless Telephony Application Interface standard, which had several other handy uses:

<a href="wtai://wp/mc;+44-1386-871490">Call GJB Enterprises</a>

Unfortunately nearly all RFC 3966-related techniques are worthless desktop/VoIP scenarios where Skype is the primary method of telephony. Skype, on the desktop, currently accepts two dialing protocols. The first being their proprietary method:

<a href="skype:+44-1386-871490">Call GJB Enterprises</a>

The second supported method Callto is actually another proprietary protocol that was introduced by Microsoft for NetMeeting 3.

<a href="callto:+44-1386-871490">Call GJB Enterprises</a>

Now if links using either the Skype or Callto protocols are accessed via a modern mobile browser, such as the iPhone, the OS simply decides that they are malformed Tel links and reformat them the same way it wants me to call some baseball statistics. So it could be argued that a hobbled together best practices approach would be to use VoIP links and assume mobile browser correction.

A Skype Call Me Widget

A Skype Call Me! Widget

However this might be confusing to they vast majority of desktop users who are not VoIP users, and if why both Skype and Google Voice provide a clunky, but less confusing UX alternative…the Call Me widget. Skype’s Call Me! widget is the less sophisticated of the two approaches. Essentially it is a link that still uses the Skype protocol, but uses an image for a clickable element rather than text.

A Google Voice Call Me Widget

A Google Voice Call Me! Widget

Google Voice, formally Grand Central, takes a different tact. If you click on a Google Voice Call Me! widget, you will be asked to enter your phone number and then a 3rd party caller/bridge system will connect your phone number to the number the widget is synced with.

So most people would likely agree that an ideal solution is not on the table, and that this is a topic that noone would say that is at the top of their interactive concerns lists, however, I’d argue that the standardization of this quirky little interactive moment (on a hardware and software level) is going an interesting little sidestory in the coming years.

Originally posted by Dakota Brown on April 8th, 2009 at 9:51 am  Permanent link to this post