The AM 6040 Ambient Microphone Unit is used to connect an ambient microphone (sold separately) to pick up background sound in the conference room. This optional device can be used as a back-up source for interpreters or for teleconferencing links when no microphones are switched on. The compact unit is typically mounted under the table, inside a floor box or in the ceiling. The AM 6040 loops into the DCS-LAN daisy chain. Works with the DCS 6000 System only.