Which Cisco TelePresence System component controls the light shrouds on a Cisco TelePresence 3010 or 3210 system?

Which Cisco TelePresence System component controls the light shrouds on a Cisco
TelePresence 3010 or 3210 system?

A.
Audio/Video Expansion Box.

B.
Cisco TelePresence System Secondary Codec/

C.
Auxiliary Control Unit.

D.
Dimmer Box.