Steps to reproduce the issue

So I created a field in XML file with type="telephone"

Expected result

Auto formatted telephone number based on Site Location/TimeZone maybe.

Actual result

The telephone number is as is and shown exactly as it is entered.

Additional Comment

There is a JHhtmlTel class that in understanding of the code, it will supposed to format a telephone number based on the chosen format ($displayplan). But by following how the code works, on line #36, it will explode the variable $number with . delimiter. That line of code assumes that the supplied number is already formatted with dots as delimiter, why?

Anyways, there is no documentation for field type telephone. How do I use it to auto format a telephone number?