LG RZ-37LZ55 remote control port

[qwik_tune]

Hi
   What is the purpose of the remote control port
on a  LG RZ-37LZ55 TV.

The remote had stopped working so
I have replaced the Ir board on the TV and there is no difference.
but i have read that if you plug in a 1/8 jack plug  in the remote control port and then remove
it the remote will work. It did but only for about 10 Mins.

So my problem appears to be the remote control port
but i cant for the life of me see what the point of the  remote control port is for


Any help very much appreciated.