coax cable on technics sx- kn300

[chas]

I have just bought a technics kn300 keyboard and it has been fitted with a coax cable coming out of the back right hand corner, can anyone tell me what this is used for or what it may have been connected to. thankyou chas.

 

[Burn4Him]

here is a link to help find the manuel, hope it helps

http://www.know-your-keyboard-piano.com/technics-keyboard-manual.html