Solved! I bought a Splitter for my RIG Pro 500Hx. Microphone isn't working

Solution
Those headphones may have different 4 pole connection than the adapter you got, or the adapter may be faulty. There are at least two different 4 pole connectors, they have the ground in a different spot. I'd try another model of adapter and/or contact Plantronics support. Also test them with a system with a single 4 pole jack like a phone.
Those headphones may have different 4 pole connection than the adapter you got, or the adapter may be faulty. There are at least two different 4 pole connectors, they have the ground in a different spot. I'd try another model of adapter and/or contact Plantronics support. Also test them with a system with a single 4 pole jack like a phone.
 
Solution