different letters, same sound, is a...?

Greetings,

I'm looking for a word, along the lines of homophone, homograph, etc,
for "two letters that look different but have the same spoken sound".
I've found contrasting definitions for "homoglyph", but I believe the
above would be its opposite.

Assume the same system of writing for the two letters. If there is a
different word used when crossing writing systems, I'd be interested
to know it as well.

thanks!


/Daniel


hrm, was just considering punctuation while proofreading the above.
How about (for extra credit :) a word for "two symbols with the same
function"?