Why href=“tel:false” gives 32573 in phone dialer?

Question

When clicked on this link from a mobile it opens dialer app with number showing as 32573, where does this 32573 come from? and if you make it "true" it shows 8783.

<a href="tel:false">Click to call</a>

Answer 1

It's the numbers that correlate with the letters on a telephone keypad.

Example

555-TRUE = 555-8783