Long CW key and headphone cable, isolation? shielding?

BL7IB

I am new to Flex6400.

I am going to make a cable to extend the CW key input and headphone output to another room.    The cable will run approximately 25 meters.    Should I choose shielded cable?   

Before I buy Flex I presumed shielding everything is good but another post recommend no STP (Shield Twist Pair network cable) to prevent ground loop.    

Should I build isolation circuitry to prevent RF get into the CW key input / headphone output?  (such as 4N35 optical coupler for CW / back-to-back diodes for audio)    or does FlexRadio already did this internally?

K9SO

BL7IB

Thanks for reply.   I am not QRO so I will try to build with simple unshielded cable.    

Before I buy my Flexradio I played with another QRP radio that the CW key input directly go into the microcontroller without protection.     I believe it is not the case with this well-engineered radio.