remote cable

[Doyle]

I have just bought a rather vintage CX5M  Y*m*h* keyboard, the one with
a screen and the whole shebang.
It has a Cassette out cable for recording data, with a normal DIN plug
on one end and on the other end 2x1.5 mm, marked "ear" and "Mic", there
is also a smaller plug with "remote" written on it. I know this cable is
for plugging into a cassette player, and all that, but I don't have
access to one with a "remote" feature. I would like to know exactly how
the "remote" plug is used, so that I can modify an existing player to
suit my needs.