I found out today that the location header of an HTTP redirect can be a tel:+ URI and phone's will actually ask you whether you want to call that number.

▲

Aachen 2 hours ago | parent | next [-]

Did you know that you can assign arbitrary programs (protocol handlers) to arbitrary protocols?

▲

mediumdeviation 14 hours ago | parent | prev [-]

Links can have that as their href and it will also work as you'd expect. It's the telephone equivalent of the more well-known mailto: scheme

	▲	econ 13 hours ago \| parent [-]
		Now we should add a ?message= query string to be read out loud in the users voice.