I have a Digi9636. Does anyone know what the controls "Channels Thru' and 'Passthru' are supposed to do? Thanks.

Here is the output from 'amixer contents'

numid=9,iface=MIXER,name='Channels Thru'
  ; type=BOOLEAN,access=rw------,values=18
  : values=off,off,off,off,off,off,off,off,off,off,off,off,off,off,off,off,off,off
numid=14,iface=MIXER,name='Passthru'
  ; type=BOOLEAN,access=rw------,values=1
  : values=off

Here is the output from 'amixer' when the RME is in default status.

Simple mixer control 'Channels Thru',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right - Rear Left - Rear Right - Front Center - Woofer - Side Left - Side Right - Rear Center - ? - ? - ? - ? - ? - ? - ? - ? - ?
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
  Rear Left: Playback [off]
  Rear Right: Playback [off]
  Front Center: Playback [off]
  Woofer: Playback [off]
  Side Left: Playback [off]
  Side Right: Playback [off]
  Rear Center: Playback [off]
  ?: Playback [off]
  ?: Playback [off]
  ?: Playback [off]
  ?: Playback [off]
  ?: Playback [off]
  ?: Playback [off]
  ?: Playback [off]
  ?: Playback [off]
  ?: Playback [off]
Simple mixer control 'Passthru',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]