Name: Plantronics Audio 400 DSP Driver
Author: Plantronics

Question 1

Install fails or stalls?

Accepted Answer

Disconnect the Audio 400 DSP, run the installer as administrator, and temporarily disable antivirus. If Windows blocks an older Plantronics package, install in Windows 7 compatibility mode or use the generic USB Audio driver.

Question 2

Device not detected?

Accepted Answer

Try a different USB port directly on the PC, not a hub; check Device Manager for “Unknown USB Device” or disabled audio endpoints; set the headset as default playback/recording device.

Question 3

Version conflicts with Plantronics/Poly software?

Accepted Answer

Uninstall older Plantronics Hub/Control Panel and duplicate Audio 400 DSP entries in Device Manager, reboot, then install one current package. Avoid mixing generic USB audio and vendor drivers.