Partyline: Can I use a Sennheiser HMD25-1 headset with my RS-601 beltpack?
Yes, the Sennheiser HMD25-1 headset should be compatible with Clear-Com RS-500, RS-600 and RS-700 series beltpacks. Same for most Clear-Com 4-pin XLR headset applications. The HMD25-1 uses a dynamic balanced mic element, wire it as an unbalanced mic element by connecting the Black and Shield together on pin 1.
HMD25-1 Wiring to 4-pin female XLR
Pin 1 – Black & Shield (mic ground)
Pin 2 – Red (mic hot)
Pin 3 – Grey & White (earphone ground)
Pin 4 – Yellow & Green (earphone hot)
Wiring diagram for the HMD25-1 headset: