Microphone ground connection - Flex-6400M

Thomas NE7X

I have a microphone distribution switch box in my shack where I route my one single desk microphone to multiple transceivers (ICOM/Yaesu). My question is how do I build a cable for my distribution switch box to connect to a 6400M? Per the 6400M User Guild (Section 4.3.19) it states the plug on the 6400M is a balanced input and to connect the shield (Negative) side of the microphone cable to the RING on the plug and not to the ground shield sleeve of the plug. The switch distribution box has all the cable shields connected to chassis earth ground. It is OK to connect earth ground to the plug RING or do I need to have some isolation of the microphone ground shield when I connect it to the RING of the plug ?

Thomas NE7X

Anyone out there that can help answer my query?  How do I build/wire a non-balanced audio interface grounded shield microphone cable to a 6400M ? Is it OK to connect the earth chassis ground to the RING? Do I need an isolation interface?

Tim - W4TME

Wire it like a balanced mic connection.

Thomas NE7X

Tim
Thanks for the reply to my query, however I'm still a bit confused. The cables coming from from my microphone distribution switch box are unbalanced, with the cable shield earth chassis ground. When you say, "Wire it like a balanced mic connection," How do I wire this to the 6400M?  Does the grounded shield go to the RING or the ground pin on the 3 pin 3.5mm plug? Do I need a xformer to convert the unbalanced to balanced?
Thomas NE7X...

Tim - W4TME

In a balanced wiring configuration, the shield (ground) and ring (MIC-) are not electrically connected.