
25
EXT. MIC PHANTOM POWER -
This parameter controls the +48V phantom power for the external ACU talk-
back mic. This should only be turned on when using an external microphone that re48V phantom
power. The available settings are off and +48V. The default is off.
TALKBACK ENABLE -
This parameter controls the different talkback modes. Available options are as follows:
• rcu or ext. mic – In this mode, the RCU talkback button enables the RCU talkback mic and the remote
talkback switch on the ACU enables the external talkback mic.
• rcu mic only - In this mode, either the RCU talkback button or the remote talkback switch on the ACU
enables the RCU talkback mic.
• ext. mic only - In this mode, either the RCU talkback button or the remote talkback switch on the ACU
enables the external ACU talkback mic.
• The default is rcu or ext. mic.
CONTROL MODE -
This parameter configures how the RCU talkback button and the remote talkback switch
on the ACU operate. Available options are as follows:
• momentary – talkback is enabled only when the switch is pressed and held (closed)
• latch – talkback is toggled with each press of the switch
• The default is momentary.
DIM ON TALKBACK -
This parameter controls how much the speaker / sub output attenuates when talkback
is active. Available range is -30dB to 0dB in 0.5dB steps. The default is -20dB.
Nifty fact: The Talkback output connector on the m905 comes configured such that it outputs the
talkback signal only when the talkback switch has been pressed. By moving J3 and J4 on the main pcb
inside the m905, the Talkback output connector can continously output the signal from the external
Talkback microphone amplifier. This allows the user to utilize the external microphone input amplifier
as a high quality stand-alone preamplifier (!)
To set the Talkback output mode: Disconnect the m905 from its AC power by unplugging the AC power
cable. Use a #2 Phillips screwdriver to remove the top cover from the m905. There are 8 screws to re-
move on the top cover, 4 on the top and 2 on each side. Be careful to discharge any static electricity on
the outside of the chassis before touching any of the jumpers inside the m905. Refer to “Figure m905
Main PCB Jumper locations”
page 40
, to locate J3 and J4.
MUTE / (SOLO)
There are no setup parameters associated with the mute / (solo) control. In setup mode, the mute /
(solo) button functions exactly as it does in normal operation mode.
11 General Setup
Other general setup options and information are accessed from the setup screen by pressing the MONO
button. Once in any of the general setup modes, pressing the MONO button again advances to the next
general setup screen (pressing repeatedly will scroll through all the different modes and wrap to the
beginning once the last mode has been reached). General setup parameters are as follows: