The following guide will help you to make Plantronics headset buttons work.

• Scancodes can be discovered by evtest:

  sudo evtest

• Keynames can be discovered in linux/input.h:

  less /usr/src/linux-headers-$(uname -r)/include/uapi/linux/input.h

• Vendor ID and Product ID can be discovered by lsusb:

  lsusb | grep -i plantronics

1. Create file /etc/udev/rules.d/70-plantronics.rules with the following content:

   ACTION!="add|change", GOTO="xorg_plantronics_end"
   KERNEL!="event*", GOTO="xorg_plantronics_end"
    
   ENV{ID_VENDOR_ID}=="047f", ENV{ID_MODEL_ID}=="c013", ENV{ID_INPUT_KEY}="1"
   ENV{ID_VENDOR_ID}=="047f", ENV{ID_MODEL_ID}=="c013", RUN+="keymap $name 0xFFA000B1 volumeup 0xFFA000B2 volumedown 0xffa000b5 micmute 0xffa000b7 phone 0xffa000ab unknown"
    
   LABEL="xorg_plantronics_end"

2. Reload udev rules:

   sudo udevadm control --reload

3. Unplug and plug again the usb device.
4. Enjoy!

1. Create file /etc/udev/rules.d/59-plantronics.rules with the following content:

   ACTION!="add|change", GOTO="xorg_plantronics_end"
   KERNEL!="event*", GOTO="xorg_plantronics_end"
    
   SUBSYSTEMS=="usb", ENV{ID_BUS}=="", IMPORT{builtin}="usb_id"
    
   ENV{ID_VENDOR_ID}=="047f", ENV{ID_MODEL_ID}=="c013", ENV{ID_INPUT_KEY}="1", ENV{ID_INPUT_KEYBOARD}="1"
    
   LABEL="xorg_plantronics_end"

2. Create file /etc/udev/hwdb.d/60-keyboard.hwdb with the following content:

   # Plantronics .Audio 648 USB
   keyboard:usb:v047FpC013*
    KEYBOARD_KEY_ffa000b1=volumeup
    KEYBOARD_KEY_ffa000b2=volumedown
    KEYBOARD_KEY_ffa000b5=micmute
    KEYBOARD_KEY_ffa000b7=phone
    KEYBOARD_KEY_ffa000ab=unknown

3. Reload udev rules:

   sudo udevadm hwdb --update
   sudo udevadm control --reload

4. Unplug and plug again the usb device.
5. Enjoy!